Ans. (b) : Four quadrant for drawing orthographical • In 1st angle projection H.P.

rotates in clockwise
projections are numbered anticlockwise. direction and comes below X-Y line–

• In 3rd angle projection, H.P. rotates in clockwise

• In projection process plane is rotated as clockwise direction and comes above X-Y line.
direction.
1. For drawing first quadrant projection, HP is rotated
clockwise, then it comes below X-Y line, but V.P.
remains same. Then for first quadrant–

102. With reference to given figure, for making plan

(Top View) in 1st angle as well as in third angle
the direction of looking is_____.
(a) Top to upwards
(b) Top to downwards
2. IInd quadrant, (c) Different for 1st angle and 3rd angle
(d) None
Ans. (b) : With reference to given figure, for making
plan (Top view) in 1st angle as well as in third angle the
direction of looking is top to downwards.
(∵ HP rotated clockwise and comes on VP)
3. IIIrd quadrant,

(H.P. comes above X-Y line)

4. IVth quadrant, • In first angle of projection, projections are drawn opposite
to the viewer side and in third angle of projection,
projections are drawn same to the viewer side.
• In India and Europe first angle of projections are used.
103. With reference to Fig., in the 1st angle
projection:
(a) Observer is between object and plane of
(H.P. comes on) projection
(b) Plane of projection is between observer and
object
(c) Object is between observer and plane of
projection
(d) Order of (a), (b) and (c) can be changed.
Ans. (c) : With reference to fig., in the 1st angle
projection, object is between observer or viewer and
plane of projection.

101. Two forms of orthographic projections are:

(a) 1st angle (b) 3rd angle
nd
(c) 2 angle (d) (a) and (b)
Ans. (d) : Two forms of orthographic projections are–
1. 1st angle • In this projection system, plane of projection
2. 3rd angle assumed to be a non-transparent.

Engineering Drawing 163 YCT

104. With reference to given Fig., in 3rd angle (a) (ii) (b) (i)
projection: (c) either (i) or (ii) (d) Both (i) and (ii)
(a) The object is between observer and plane of Ans. (b) : From the figure, given in question, figure (i)
projection shows the 1st angle of projection system because in this
(b) Observer is between object and plane of figure, object is lie between plane of projection and
projection observer.
(c) Plane of projection is between observer and
object
(d) Order of (a), (b) and (c) can be changed
Ans. (c) : With reference to the given fig. in 3rd angle of
projection, plane of projection is between observer and
object.

Figure (ii) shows the symbol of 3rd angle projection

because the plane is lie between the object and observer.
• In this case, plane of projection is assumed to be
transparent. 107. Choose the correct orthographic view as per
the direction shown in isometric
105. The recommended symbol for indicating the
angle of projection shows two view of the
frustum of a_____.
(a) Square pyramid (b) Triangular pyramid
(c) Cone (d) Any of these
Ans. (c) : The recommended symbol for indicating the angle
of projection shows two view of the frustum of a cone.

Ans. (d) : For an isometric view, given in question,

• Symbol of 1st angle projection–
according to shown direction.

• Symbol of 3rd angle projection–

106. Figure–(i) and (ii) below show the method of

obtaining 1st and 3rd angle projection symbol.
Which one shows the principle of 1st angle
projection symbol?
108. Find out the plan/top view of the object as per
the direction of arrow in isometric view?

Engineering Drawing 164 YCT

Ans. (a) : The plan/top view of the given object as per • The line X-Y of intersection of both principal
the direction of arrow in isometric view in given figure. planes is known as reference line.
• When drawn the projection of object on drawing
paper, reference line works as basic line between
plan and elevation.
112. Figure given below shows_____principal planes
for orthographic projection.
It's orthographic views are–

109. An object is shown by more than one views in a (a) 4 (b) 3

drawing. It is called_____. (c) 1 (d) 2
(a) Isometric projection Ans. (d) : Figure given in question shows 2 principal
(b) Oblique projection planes for orthographic projection.
(c) Perspective projection • These principal planes are – (1) Horizontal plane
(d) Orthographic projection (HP) (2) Vertical plane (VP).
Ans. (d) : An object is shown by more than one views 113. In the figure the shaded vertical plane is known
in a drawing. It is called orthographic projection. as_____.
• In this projection, projectors (or sight rays) are
parallel to each other and perpendicular to the plane.
Fig.
110. Orthographic projection is a_____projection.
(a) One view (b) Two view
(c) Multi view (d) Four dimensional
Ans. (d) : Projection in which when the projectors are
parallel to each other and perpendicular to the plane, is
called orthographic projection. (a) HP (b) VP
• This projection is a multi views projection because (c) AVP (d) All of these
in this projection for the complete description of the
Ans. (c) : In the figure given in question the shaded
3D object at least two or more than two projections
vertical plane is known as AVP.
are drawn.
• This plane is used for showing or drawing the side
• Front view projection is drawn on vertical principal
view of an object.
plane, top view projection on horizontal plane and
other any side view projection on an auxiliary plane. 114. We can draw the orthographic projection
in_____angles.
111. The two principal planes (HP and VP) are
............ degrees to each other. (a) 1st and 2nd (b) 1st and 3rd
st th
(a) 30° (b) 60° (c) 1 and 4 (d) 2nd and 4th
(c) 90° (d) 180° Ans. (b) : We can draw the orthographic projection in
Ans. (c) : Two principal planes (HP and VP) intersect 1st and 3rd angles.
to each other at 90o. • We can not draw the orthographic projection in 2nd
and 4th angles because, in this system–
nd
2 angle projection,

Engineering Drawing 165 YCT

• When we draw orthographic projection, HP and VP
both come above X-Y line.

• Hence front and top view projections both are

overlapped to each other.
4th angle projection, • From the figure, object (1) is placed below HP and
object (2) is placed on HP.
• When the object is placed in 3rd quadrant the
projection of that is called 3rd angle of projection.
118. Figure below shows the principle of_____angle
projection.
• When we draw orthographic projection, HP and VP
both come below X-Y line.

• Hence front and top view projections both are

overlap to each other.
• Due to this difficulty we can not use these systems
in orthographic projection.
115. On auxiliary vertical Plane (AVP). _____view
is projected. (a) 3rd (b) 1st
(a) Front (b) Top (c) Both (a) and (b) (d) None of these
(c) Side or end (d) Any one of these Ans. (b) : Figure above (given in question) shows the
Ans. (c) : Side or end view is projected on auxiliary principle of 1st angle projection, because the object is
vertical plane (AVP). situated between the plane of projection and viewer or
• Some times some features of an object lie on its left observer.
or right side. Top and front views will not be • In this case, projection of plane considered to be
sufficient to show these features in their true shape. non-transparent.
In such cases, the objected is projected either on a 119. Figure below shows the principal of_____angle
left or right side plane. orthographic projection.
• This side plane is known as auxiliary plane.
116. In 1st quadrant (i.e. for 1st angle projections)
the object is placed_____.
(a) On HP (b) Above HP
(c) Below HP (d) (a) or (b)
Ans. (d) : In 1 quadrant (i.e. for 1st angle projections)
st

the object is placed above H.P. and some times on HP.

(a) 1st (b) 3rd

(c) 4th (d) 2nd
Ans. (b) : Figure given in question shows the principle
of 3rd angle of orthographic projection, because plane of
• From, the figure, object (1) is placed on HP, and (2) projection is situated between object and observer.
is above HP and in front of VP.
117. In 3rd quadrant (i.e. for 3rd angle projections)
the position of the object with reference to HP
is_____.
(a) On HP (b) Below HP
(c) above HP (d) (a) and (b)
Ans. (d) : In 3rd quadrant (i.e. for 3rd angle projections)
the position of the object with reference to HP is on HP • In this projection system, plane of projection is to
or below HP. be considered as transparent.

Engineering Drawing 166 YCT

 EXAM POINTS
A geometrically represented image of an object Orthogonal projection is also known as –
obtained on a surface or place is called 2D projection
Projection of the object Pictorial projection is also knows\n as single view
The straight lines, which are drawn from various projection where as orthogonal projection is known
as– Multi view projection
points on the contour of an object to meet a plane is
called as – Line of sights, Perspective, axonometric and oblique projections
comes in the category of – Pictorial projections
or projection rays
One point, two point & three point projections are
or projectors the types of – Perspective projection
The straight lines from the object to the projection In perspective projection, when any of principal axis
plane are called as – Projectors intersects with projections plane ( or has one
or Projection rays vanishing point) is called –
In the projection of an object, according to One point (Parallel) projection
projection rays, they are classified in two types When projection plane intersects two of Principal
which are – Prospective or central projections axis (or it has two vanishing points) is called–
and parallel projections Two point (Angular) Projection
According to obtaining views of an object in In perspective projection , when all three axis
projection process, types of projection are classified intersects with projection plane, there is no any
as – Single view projections principal axis which is parallel to projection plane (
i.e. it has three vanishing point) is called–
and multi view projections
Three point (oblique) projection
Parallel projections are those, in which projections
Realistic view of a 3D object is provided by–
rays are – Parallel to each
Pictorial projection
other
The projection in which, projections are not
In parallel projections, observer is situated at what perpendicular to the plane of projection one
distance from the object – Infinite distance dimension ( i.e. front face) of the object is parallel to
Perspective projections are those, in which horizontal, second is vertical to the horizontal and
third is at an angle of 30° or 45° to the horizontal is
projection or visual rays are – Converge at a called– Oblique projection
point (called view port) In oblique projection, one dimension (i.e. front face)
In perspective projections, observer is situated at of the object is shown in equal shape and size
what distance from the object – Finite distance because it is – Parallel to horizontal
In parallel projections, size of projections is – Oblique projections are generally in 3 types which
Equal to the size of object are – Cavalier, Cabinet and
In perspective projections, size of projection is – Clinographic Projections
Smaller than the size of object In oblique projection, the projection in which
projection lines make an angle of 45° with the plane
Applications of the parallel projections are in – of projection , all dimensions are in full size but one
Architecture, computer aided designs etc. makes 45° angle to the horizontal is known as –
Applications of the perspective projections are in– Cavalier projection
Animation, visual simulation etc. In oblique projection, the projection in which
The projection in which the description of the object projection line make an angle with the projection
is completely understood in one view is known as – plane, it becomes about 1 both the are s by
2
Pictorial Projection decreasing scale is knows as– Cabinet projection
The projection which shows all three dimensions in
In cavalier and cabinet projections, main face of the
on view called as –
object is made parallel to projection plane (or
Pictorial projection are view parallel to horizontal axis) but the projection in
Pictorial projection is also known as– which main face is stated an angle , is known as –
3D projection Clinographic projection

Engineering Drawing 167 YCT

 In perspective projection, the projecting lines or Isometric view is drawn by the use of –
visual rays converge at a point hence it is termed as Actual scale
–
Isometric scale converts true lengths of the object
Convergent projection
into isometric lengths which are foreshortened to–
Perspective projection are not used by engineers for 8.816 times of actual length.
manufacturing because –
Length of isometric scale is equal to the –
This view does not reveal
The exact size and shape 2 (approx 0.816) time the length
3
The projection which may be used in marketing
where a natural view of a product is desirable is – of actual scale
Perspective projection In isometric projection, when lines are drawn
parallel to isometric axes, the length are
The projection in which only one view showing al foreshortened to – 0.816 times to actual length
the three dimensions of an object when it drawn on a
projection plane and the orientation of object is kept Generally in isometric projection of an object the
in such a way that its three mutually perpendicular dimensions of its length and width are at an angle of
edges will remain inclined to the projection plane, is 30° to the horizontal and the dimensions of height
called – are at – 90° to the horizontal
Axonometric projection The dimensions of projection in isometric projection
In axonometric projection, projection lines are are – 18.4% less than the actual
parallel to each other and perpendicular to which dimensions of the object
plane – Projection plane Isometric view of a circle is – Ellipse
In this projection, observer situated at– a square will appear on a isometric drawing as a –
Infinite distance Rhombus
Axonometric projection are generally three types A rectangle will appear on a isometric drawing as a
which are – Isometric, diametric – Parallelogram
and trimetric projections
In drawing which view shows the actual size of an
An axonometric projection in which, if all three object – Isometric view
faces of a cube make unequal angles with plane, is
known a – Trimetric projection In cavalier projection, ratio between the length of
principal face lines and lines is – 1:1
An axonometric projection in which, is only two
faces of a cube make equal angle with plane, it is In cabinet projection, ratio between the length of
known as – Diametric projection principal face lines and reducing lines is – 2:1
An axonometric projection in which, when all the The size of isometric projection of an object is
three faces of a cube make equal with the plane, it is ............ than size of isometric view – Smaller
known as – Isometric projection Vertical edges of an object is shown by ....... in
The projection in which an object is inclined and isometric view – Vertical lines
tilted in such a way that all its mutually At the time of isometric projection, of an ellipse, it is
perpendicular planes are equally inclined to the drawn by the method of– Four centre method
observer, is known as – Isometric projection
An object, which is asymmetric , generally shown
Two isometric axes are inclined to each other at – by – 3 views
120° Perspective projection are generally used in –
Isometric axes are inclined to horizontal or base line Civil Engineering
at – 30°
For the projection of any object which elements are
Isometric axes are inclined to vertical at – 60°
necessary – Object, observer
The lines which are parallel to isometric axes are
projection plane projector
termed as – Isometric lines
For the easily making of isometric view and easily
The line which are parallel to isometric axes are
termed as – Non- isometric lines measurement of dimensions from the drawing which
scale been used now a days – Read scale
The planes representing the faces of the cube as well
as other planes are parallel to these planes are For isometric projections, which scales are used–
termed as – Isometric scales Isometric scales
Engineering Drawing 168 YCT
 Generally the types of pictorial projection which is There are four quadrant system which are made by
used by architecture is – Isometric projection the intersection by planes. They are–
The value of isometric factor is – 0.816 1st, 2nd, 3rd and 4th quadrant systems
The view in which all three plane faces makes When the plans of projection are extended beyond
unequal angle with each other is– Trimetric view their line of intersection , they form–
In oblique view – One face is parallel to H.P. Four quadrant or dihedral angles
and other is inclined to H.P. The quadrants in the eng. drawing system, are
In oblique view, the receding line is mostly numbered as I , II, III and IV , in which direction–
inclined........... the H.P. – 45°
Counterclockwise direction
In oblique view, the lines which are inclined, are
Second quadrant is that in which object is situated–
called – Receding lines
Front of VP and above HP
Pictorial projection are used generally in –
Second quadrant is that in which object is situated in
Architectural
– Behind the V.P and below HP
or Surveying works
Fourth quadrant is that is which object is situated in
In object projection, the dimensions of the object
which are parallel and vertical from horizontal seen – Front of VP and below H.P
like – Larger than true length In orthographic projection system, there are two
In oblique projection , the dimension which is reference planes used they are – H.P. and V.P
inclined to horizontal with 30° or 45° seems like – Both two principal or reference plans HP and V.P
Smaller than true length termed as – Horizontal plane and
In isometric view, all dimensions of an abject are– Vertical plane respectively
Real Both reference planes intersect to each other at –
Isometric projection dimensions of height are drawn 90°
to 90° from – Horizontal
In orthographic projection system there are only two
When the projections are parallel to each other and
projection system are used . they are –
perpendicular to the plane, the projection is called as
– orthographic projection Ist angle projection and IIIrd angle projection
The projection method in which, an object is is the symbol of –
represented y two or three view on an perpendicular
projection planes is – Ist angle projection
Orthographic Projection
is the symbol of –
According to the no, of views, orthographic
projection is also known as – IInd angle projection
Multi views Projection
In orthographic projection , each projection view is the symbol of –
represents how many dimensions of an object –
2 Dimensions IIIrd angle projection

For the complete description of 3D object, at least

two or three views are required. For this condition is the symbol of –
which projection method is used – VIth angle projection
Orthographic projection In orthographic projection system, IInd and IVth
The projection method, which is required for the angle projection methods are not used due to –
complete description of the shape on any complex Overlapping of projections
shaped object is – Orthographic projection
In the first angle of projection, object is situated in–
The shape of complete shaped object can never be
First quadrant
described by a single view. Hence at least 2 or 3 or
more than 3 view are required for knowing this. In In the fist angle of projection , object is lies
this case the used projection method is – between–
Orthographic projection The observer and the projection plane

Engineering Drawing 169 YCT

 In the third angle of projection, the plane of In third angle of projection, right side view of an
projection lies between – Observer and object object is drawn to – Right side of front view
The plane of projection of third angle of projection In the first angle of projection, left side view of an
method is assumed to be– object is drawn to – Right side of the elevation
Transparent The plane which is used for drawing the side view of
The plane of projection of first angle of projection an object is called – Auxiliary plan
method is assumed to be – Non-transparent Auxiliary planes are also know as –
When the principal plans (i.e. HP and V.P) intersect Profile planes
to each other, the intersection line made by those In orthographic projection system, when only two
planes is called – Reference line views (ie. front and top views) are not sufficient to
In the orthographic projection system, the reference convey the actual shape of an object then extra view
line is denoted by – X–Y line required they called – Auxiliary views
HP and VP is located below and above the reference In India , which type of orthographic projection
line (X – Y line) respective in – method is used – Ist angle of projection
Ist angle of projection The method of orthographic projection which is
HP and VP is located above and below the X – Y used in India and Europe. is –
line respectively in – IIIrd angle of projection IST angle of projection
The projection system in which projection are drawn The method of orthographic projection which is
opposite to the viewer side is – used in USA, is – IIIrd angle of projection
Ist angle of projection The planes on which various projection are drawn
The projection system in which projection are drawn are called – Planes of projections
same side to the viewer, is – The projections is orthographic projection system,
rd
III angle of projection are obtained by drawing .......... from the object to
the planes – Perpendiculars
In first angle of projection, front view is draw .......
X – Y line – Above The reference line ie. X – Y line is also termed as–

In first angle of projection, top view is drawn in Ground line

which direction of X – Y line – Below When the auxiliary plane is perpendicular to H.P.
In third angle of projection, front view is drawn in and inclined to the V.P. it is called –
which direction of X –Y line – Above Auxiliary vertical plane (A.V.P.)
In third angle of projection, top view is drawn in When the auxiliary plane is perpendicular to the VP
which direction of X – Y line – Below and inclined to the H.P. is called –

In orthographic projections, front view is termed as Auxiliary inclined plane (A.I.P.)

– Elevation Projection on an auxiliary lane is called as –
In orthographic projections, top view is termed as– Auxiliary view
Plan The projection of the object on the auxiliary vertical
In orthographic projection front view or elevation is plane or profile plane is called as –
drawn on which plane – Vertical plane (V.P) Side view of side Elevation
In orthographic projection, top view of plane is or profile view
drawn on which plane – Horizontal plane (H.P) Auxiliary vertical plane is also known as –
In the fist angle of projection right side view is Profile plane
drawn to – Left side of front view In parallel rays projection, observer is situated at
or elevation what distance from the object – Infinite
In the third angle of projection, left side view of on In parallel projection, the size of projection is –
object is drawn to – Left side of front view Equals the original object
Engineering Drawing 170 YCT
 In perspective projection, projection rays are When point is situated behind the VP, its plan will
intersect at – View point always be– Above x-y line
The projection method in which, object appear When a point is situated below H.P. its elevation
smaller the farther away they are, is – will always be– Below x-y line
Perspective projection When a line is situated in front of VP, its plan will
Application of perspective projection as – always be– Below x-y line
Animation, visual Distance from VP of any object or point be seen in–
Plan view
Applications of parallel projection are in –
Distance from HP of any object or point could be
Architecture, CAD etc.
seen in– Elevation view and side view
In fist angle of projection, reference line or X – Y
When the distance of a point from HP is x, it can be
line works as – Ground line
seen in– Elevation
In third angle of projection, ground line is situated–
When a point is situated y distance from VP it can
At some finite distance
be seen y distance from x-y line in– Plan
below X – Y line
In any quadrant, maximum possible position of a
When the object is shown by its front face view is
point will be– 4
known as – Front view
When a point is situated in vertical plane (VP) its
Side view is also known as –
plan will be– On the x-y line
End view, or profile view
When the plan of a point is x distance from x-y line
In orthographic projection , when the plane of it will be distance from– VP
projection is situated between point of right and
When the projection of a point is in x-y line,
object , its projection seems like –
Smaller than original size , it will be situated–
In orthographic projection, when the object is Both on the plane
situated between the point of sight and plane of When the elevation of a point is in x-y line, i.e.
projection, its projection like –
, it will be situated in–
Larger than original size
When the observer or point of sight is situated at
infinite distance, the projection become –
Horizontal plane (HP)
Parallel to each other
When a point is situated both on the plane, its
Point is defined as a circle which has– projection will be– In x-y line
Zero radius
X-Y line is also known as– Reference line
Point is represented on drawing sheet by– Dot
When a point is situated in fourth quadrant, its
When two or more than two non-parallel lines position will be below HP and– In front of VP
intersect, at the intersection what is produced–
When a point is above ground and behind VP it is
A point situated in– Third quadrant
A point may be situated in space in which When a point is above HP and behind VP it will be
quadrants– Any one of the four quadrants situated in– Second quadrant
A point is situated below HP, its elevation is ...... When a point is above ground and in front of VP, it
from the x-x line– Below will be situated in– Fourth quadrant
The plan of a point is found below to x-x line, it will Shortest distance between any points is termed as–
be situated– In front of VP
Straight line
In projection of a pint in orthographic projection
The locus, made by a moving point in a specific
method, when point is situated above HP, its
direction is called as– Straight line
elevation will always be– Above x-y line
Engineering Drawing 171 YCT
 A line may occupy how many number of positions When a line is contained by both the planes, its top
in space with respect to HP and VP– and front views will be–
An infinite number Both are in x-y line
When a line is parallel to both plane i.e. HP and VP. When a line is perpendicular to VP and parallel to
Its plan and elevation both will be– HP, its side view will be–

A line of actual length and parallel to x-y line A straight line of true length
When a line is perpendicular to HP and parallel to
When a line is perpendicular to H.P. Its top view
VP, its side view will be–
will be– A point
A straight line of true length
When a line is perpendicular to V.P., its ............
When a line is situated parallel to both principle
view will be perpendicular to x-y line– Top view
planes, its side view will be– A point
No any line can be in ............ position with both
When a line is situated parallel to HP and inclined to
reference plane– Perpendicular VP, its front view will be–
When the elevation of a line shows a line of true A line smaller than true length
length, it is possible only when line is ........... to and parallel to x-y line
V.P.– Parallel
When a line is situated parallel to VP and inclined to
A line is placed inclined to HP and parallel to VP, its HP, its front view will be–
true length will be seen in– Elevation A line of true length and inclined to x-y line
When a line is placed parallel to HP and inclined to When a line is contained by horizontal plane and
VP, its true length could be seen in– situated some distance from vertical plane. Its top
Plan view or top view view will be– A line of true length

Front and top views of a line have been shown When a line is contained by VP and situated some
distance from HP, its front view will be–
below and above the x-y line respectively. This
projection is drawn in– Third angle A line of true length

When the top view of a line is point, its front view When a line is contained by both the principal
planes (i.e. HP and VP) then–
will be– A line of true length and
Its FV and TV coincide to each other in x-y line
perpendicular to reference line
When a line is placed perpendicular to HP, then it
During projection process, the true length of a line
always be parallel to– Both VP and AVP
can be found when this line is ................ to that
True size of a line is found in which plane where it
plane– Parallel
is– Parallel
When a line is parallel to both principal plane (i.e.
When a line is situated parallel to HP and
HP and VP) its side view will be– A point
perpendicular to VP, its top view will be–
When a line is parallel to both HP and VP, its front A line of true length perpendicular to x-y line
view will be–
When a line is inclined to both the principal planes,
A straight line, parallel to x-y line its– Both top and front view will be a line
The front view of a line, when the perpendicular to smaller than true length and inclined to x-y line
VP, will be– A point When a line is inclined to both the principal planes,
o its plan and elevations both have–
When a line is laying VP and inclined to HP to 8 ,
its top view will be– A line smaller than true Angles greater than the true inclinations
length and in the reference line When a line is inclined to both the reference planes,
A 25 mm long line has 25 mm long straight line in its true length will be found in– Side view
plan and elevation both. It can be placed between The inclination of the projections that represent the
HP and VP in such a way that– apparent lengths are known as–
It is parallel to both HP and VP Apparent angles

Engineering Drawing 172 YCT

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 02.
Occupational Safety and Health
1. Accident- (iv) Ignorance– There is a possibility of an accident
Unknowingly the incident which has uncontrollable even if you do not have complete knowledge of the
and sad consequences is called an accident. equipment.
(v) Curiosity– Curiosity is ingrained in human
• Workplace accidents of industrial accidents are only
nature. The more curious person becomes the victim of
those that occur due to errors in working conditions and
an accident therefore it has to be controlled by the
work performance system.
artisans working in the factories.
Causes of Industrial Accidents- Skilled human (vi) Unsafe Hand Tools– Due to improper
labour always works in a protective manner. To keep maintenance of machines, machines are also used in
yourself safe, it is necessary to have knowledge of the unsafe condition which becomes the cause of accident.
causes of accidents. In general, the main causes of Like- torn glove, mushroom headed chisel and split or
accidents are as follows- cracked handles or file etc.
(i) Carelessness– Most of the accidents in factories are
due to carelessness. While working, along with the
concern of the work, the artisan should also take
adequate care of his own and other's safety.

(ii) Loss of Interest– Sometimes the worker loses

interest in the work. In such times the chances of an (vii) Unsafe dress– Use of loose clothes, tie, muffler
accident are high. etc are also prohibited in the factory because all these
also come under the category of unsafe wear. Clothes
should be use as per the requirement of the factory.

(iii) Hastiness– Due to the pressure of the factory (viii) Unsafe Lay-out– At the time of installation of
owner or for his greater profit, the worker work faster various machines in factories, sufficient space should be
than requirement. Due to this the chances of accident left for them. Sometimes, accidents may occur due to
increase. insufficient space.
Occupational Safety and Health 173 YCT
 (iii) Dettol
(iv) Tincture Iodine
(v) Bernol
(vi) Sniffing salt
(vii) Medicated plaster
(viii) Cotton, hemp (net cloth)
(ix) Scissors, knives, safety Pin
(x) Triangular and round bandage
(xi) Medicine glass
(ix) Wrong Method of Working– Unintentionally, (xii) Drapers
many time the artisan adopts the wrong way of working. (xiii) Bamboo sticks
For example, filing with a sand paper without a handle etc. (xiv) Stretcher
(x) Lack of Cleanliness– Accidents can happen due (xv) Potassium permanganate
to improper cleaning of the shop floor. For example, Basic Life Spot– A person who is given first aid is
slipping foot on oil, stumbling anywhere etc. called a 'Basic life spot' by doctors : There are three
(xi) Lack of Discipline– Due to lack of discipline, actions in the basic life spot, which are denoted by the
the Funniment made by the employee become the cause first three letters of English A, B and C.
of accident. (i) A for Airway– Under this, it is ensured that the
(xii) Improper Arrangement of Light– Accidents victim's airway is not closed due to any foreign/other
happen due to lack of light, where the artisan works on objects.
the machines. There should be adequate lighting (ii) B for Breathing– Under this, it is ensured
arrangement. whether the victim in breathing or not. If not, he is given
(xiii) Illness or Tiredness– Sometimes the workers artificial respiration.
comes to work despite being sick or weak due to (iii) C for Circulation– Under this, it is ensured that
financial constraints and can fall due to dizziness or the pulse of the victim is running or not. If there is no
weakness, which comes under the category of accident. pulse then CPR (Cardiopulmonary resuscitation) is given
(xiv) Special precautions should not be taken to victim.
with danger substances– Special precautions should be
taken in the factories where explosive, acid or
inflammable of poisonous gases are used.
(xv) Toxication– Working in a factory while
intoxicated one has to control the accident. Such artisans
are not only themselves victims of accidents, but can also Artificial Respiration Process– If a victim is not
be danger to others. breathing, then he is given artificial respiration by the
2. First-Aid- following methods-
On the time of sudden accident or illness, the
(A) Schaffer's Method
necessary treatment given to the injured person before
(B) Sylvester's Method
reaching the doctor or taking him to the hospital is called
(C) Labord Method (Mouth to mouth respiration)
first aid. It is necessary to give proper training of Basic
(D) Artificial Respiration method
first aid to the employees working in the workshop, so
(A) Schaffer's Method– This method is used when the
that the victim can be saved easily. For this it is
victim has blisters on his back.
necessary to have the following information-
• In this method, the victim is made to lie down on his
First Aid Box– A red (+) sign is made on the first aid
stomach, and a thin pillow is placed under his chest.
box. • In this method, the following two conditions are
used to fill the body of the victim with breath-
(i) First position– Kneel down near to the knee of the
victim with his face towards his head.
• Turn the head to one side so that the mouth and nose
remain away from the ground.
• Place both your hands on the victim's back in such a
First Aid Box Material– The materials and way that both hands remain straight and all four
medicines used in first aid are as follows- fingers meet each other and they form a right angle
with the thumb.
(i) Acriflavine or Mercurochrome
(ii) Spirit ammonia

Occupational Safety and Health 174 YCT

 (C) Labord Method– It is also known as mouth to
mouth respiration. In this method, respiration is
completed by filling air directly in the mouth of the
victim.
• Mouth to mouth respiration is accomplished by
following two positions-
(ii) Second position– While leaning forward in this (i) First Position– Make the victim lie down on his
position, apply pressure on the victim's back. This back. Now put a pillow etc. under the victim's back, so
courses forward pressure on the victim's diaphragm and that his face hangs slightly backwards.
the air lungs comes out. Wait for two second and sit
down to release the pressure.
• Again lean over and apply pressure. In this way, keep
repeating this action 10-12 times per minutes until the
breathing becomes normal.

(ii) Second Position– Clean the victim's mouth

thoroughly. Now cover his open mouth with a cloth and
close his nose with one hand and forcefully blow air his
mouth. Take care that the air is out and his lungs expand
a bit. After letting out the air, remove your mouth. Keep
(B) Sylvester's Method– This method is used when repeating the above activity at the rate of 10-12 times per
there are blisters on the chest. In this method, the victim minute until his breathing becomes normal.
is made to lie down on his back. After this a pillow is
placed under his back so that his chest rises slightly and
his head is slightly lowered.
• The following two positions are adopted for giving
breath to the victim-
(i) First Position– Get down on your knees near the
victim's head. Tie half the fists of both his hands and
spread the heads straight. Now slowly bend both the
hands of the victim and bring them on his chest. Note- Out of the above three method, the third
method is becoming more prevalent because this method
can be started immediately. Along with this, it is an
effective method and it is not necessary to continue it for
a long time, while the first and second method may have
to be continued for more than an hour.
(D) Through Artificial Respiration Instrument–
(ii) Second Position– In the first position, apply
The air comes to the chamber after being filtered through
some pressure on the victim's chest with your hands.
the rubber value used in this device. Here, inlet and
After 2-3 seconds, remove the pressure and spread the
victim's hand towards his head open the fists. outlet values are fitted, which open, and close by
pressing and releasing the rubber values. Under this, air
is enter inside the victim through a mask placed on the
victim's mouth. It is a very simple process. In this the
rubber value is operated 15 to 20 times in a minutes.

Repeat the above activities as the rate of 10-12 times per

minute till his breathing become normal.
• When pressure is applied to the victim's chest, the
air inside the lungs is pushed out and the removal of
pressure, fresh outside air to enter the lungs. Thus,
the victim is assisted in breathing.
Occupational Safety and Health 175 YCT
3. Electric Shock– Generally, when electric current is Server muscle contraction,
4. 20 to 50mA
established across our body at a voltage of more than 90 breathing difficult.
volts, then we experience a shock, this is called electric Serious contraction of Heart
shock. Electrical sector is a very sensitive sector, in 5. 50 to 100mA muscle, Possible death, No
which there are possibilities of continuous accident known remedy
during work. 100mA and Severe burns, Stoppage of
6.
Cause of an Electric Shock above heart, Death certain
The main cause of electric shock is the high speed of Note- A shock caused by a current of less than 1 mA is
electric current (3×108 m/sec.) which does not adjust not felt.
with the speed of blood flow in our body and the person Safety rules for electricity– Machine operators in
gets a very strong electric shock. factories should adopt the following electrical safety
• Damages Caused to Human Body by an rules–
(i) The main switch of electricity should be installed
Electric Shock near the machine and the operator.
Due to electric shock, the following damages can (ii) Without using the plug, the machine should not be
happen to the human body, such as- operated by connecting the electric wire directly to
(i) There may be blisters on the body. the plug.
(ii) The flesh of any part may get burnt. (iii) A fire extinguisher containing carbon tetrachloride
(iii) Blood flow may occur. should be used to extinguish the fire in the electric
(iv) There may be obstruction in breathing wire.
(v) Person may faint. (iv) If any electric wire rubbing on any moving part is
(vi) A person can die due to cardiac arrest. seen, then the electrician should be called and
rectified immediately.
• Isolating a Person from Electric Contact (v) In case of any electrical fault the artisan should
(i) Switch 'off' the machine/equipment or remove the inform about it to his senior officer.
plug top from its main load or switch 'off' the main 4. Fire– Fire is a chemical reaction that occur in contact
switch of the power line. with flammable substances and heat and oxygen.
(ii) If it is difficult to do any of the above, stand on a • Important factor for the production of fire–
rubber mat, a dry wooden objector a thick plastic (i) Fuel
object etc. and pull the victim away from the electric (ii) Heat
contact. (iii) Oxygen
(iii) Carefully when getting rid of electrical contact, the Thus, in the absence of any one of the above three
victim should fall on the ground due to shock, so factors, the fire blows out.
that he does not get more hurt. • Causes of fire- The following are the causes of fire–
• The effect of electric shock on the human body (i) Loose connection of power cables.
depends on the time the current passing through the (ii) Absence of oil in the fast moving part.
body remains in contact with the electricity and (iii) Electrical short circuit or overload.
nature of the electricity (AC or DC). DC (direct (iv) Presence of flammable materials.
current) is more dangerous than AC (Alternating (v) Smoking in the factory
current). (vi) Presence of explosives.
Table related to the effect of electric current on (vii) Due to electric shock.
human body– (viii) Lack of temperature control system in heaters.
S. Current in mA. Effect of electric current (vii) Oil stained rags scattered everywhere.
N. (milli ampere) • Types of fire, methods of extinguishing and
Its shock is felt, but it is not category related table-
1. 1 to 8mA painful, that means human S. Types of Fire Remedy of Class of
can tolerate it. N. Fire-Fighting Fire
Painful shocks, but muscular 1. Carbonaceous fire To extinguish It is
2. 8 to15mA
control is not lost. (fire caused by this type of fire called
Painful shocks, Muscular wood, paper, by water, sand Class
3. 15 to 20mA control affected, so human cloth, jute and or soil 'A' Fire.
cannot tolerate it. charcoal etc.)

Occupational Safety and Health 176 YCT

 2. Oil fire (fire Foam fire It is • In this way, as a result of the chemical reaction of
caused by extinguisher called both the substances, CO2 gas is generated, which
kerosene, diesel and CO2 Class works to extinguish the fire.
and petrol). extinguisher are 'B' Fire. Note- It is used to extinguish class 'D' fire.
used to
extinguish it.

3. Gaseous fires (Fire To Extinguish It is

caused by this type Of fire called
propane, butane by Chemical Class
and LPG etc.) Like CO2, 'C' Fire.
Halon etc are
used. (c) Foam type fire extinguishers (Foam extinguisher)-
This type of device is used to extinguish the fire caused
by oily substance, but it cannot be used on electricity and
fire because both foam and water are good conductors of
4. Electric fire (fire CTC fire It is electricity.
caused by extinguisher is called • This machine produces foam along with the water
electrical wires, used to Class jet.
equipment, extinguish this 'D' Fire. • Mineral oil, soap etc substances are mixed in it with
metallic materials type of fire. Dry air pressure and filled with water to generate foam.
etc.) sand can also be • When the lever of the device is pressed, foam mixed
used. with water is generated, which extinguishes the fire
by cutting off the oxygen supply of the burning
object.

Fire-Fighting Equipment
The liquid, gas or powder that is sprayed by a fire
extinguisher is not flammable by itself, nor does it aid in
ignition.
Fire extinguishers must be available in every
workshop.
(a) Buckets filled with sand- These are used to
extinguish electrical fires. Note- It is used to extinguish class 'B' type i.e oil
• Dry sand is kept outside the workshop in buckets based fires.
painted by red colour. (d) Water based fire extinguisher (water filled
• Symbolically fire is written on these buckets. extinguisher)- This is type of device is used to
extinguisher class 'A' fire.
• It is filled with water with air pressure. Pressing the
lever produces a jet of water by which fire is
extinguished.

(b) Carbon dioxide (CO2) type fire extinguishers-

Carbon dioxide gas does not support combustion and
helps in extinguishing the fire by cutting off the oxygen
supply to the burning material.
• This type of apparatus contains sodium bicarbonate
(NaHCO3) solution and a glass bottle containing
dilute sulfuric acid (H2SO4).
2NaHCO3 + H 2SO 4  → Na 2SO 4 + 2H 2 O + 2CO 2
Occupational Safety and Health 177 YCT
(e) Dry powder type fire extinguisher- In this type of 5. Safety- The literal meaning of the word safety is to be
machine powder is filled with air pressure without water. safe. Being safe from any unwanted accidental accident,
• This powder is neither inflammable nor helpful in which affects any person or the environment around him is
burning. called safety.
• On pressing the lever of the device, the powder • Prevention from General Accident- To prevent
extinguishes the fire by stopping the oxygen supply accidents in the work area, it is necessary to keep the
to burning object. following things in mind-
Note- This device is used to extinguish class 'D' type (i) Safety signs should be posted as posters.
fire. (ii) Danger signs must be put on electrical instruments
(f) Carbon tetra chloride (CTC) type fire and machines.
extinguisher (CTC extinguisher)- It is also called halon (iii) Every machines must have a chart of precautions
type fire extinguisher. related to possible accidents caused by that
machines.
• Generally, this device can be used to extinguish all
(iv) Keep buckets filled with sand extinguishing at a
types of fires.
proper distance from fire extinguishing plant..
• This liquid envelops the burning object and
(v) keep each tool in its respective tool kit.
extinguishes the fire immediately by cutting off its
oxygen supply. (vi) The main switch (MCB) should be installed at such
places which are easily accessible by the workmen.
• It is filled with a liquid called carbon tetra chloride
(vii) First aid kit must be in every workshop.
(CCl4) or Bromochlorodi-Fluorometahne (BFC)
with air pressure. Types of Safety
• Due to the poisonous, vapour generated by this (a) Self safety
device it is kept in open places only. (b) Machine- tools safety
(c) General workshop safety
(a) Self safety- Self safety consists of the following
protections-
(i) Do not work while standing under a hanging
weight, as a fall of the weight may a serious
accident.
(ii) Never work in the workshop wearing loose clothes,
tie, muffler etc. Due to these, there is a danger of
accident due to running machines.
Note- These types of fire extinguishers are (iii) Oil funnel should be used.
especially suitable and safe to use on electrical (iv) Running machines should never be repaired.
equipment. (v) One should always walk in workshop wearing
(g) Soda acid extinguisher- It is used to extinguish boots, because there is a danger of getting injured
carbonaceous fire (such as, fire caused by wood, cloth due to iron waste coming out of the machines. Steel
and other solid flammable materials). Electric fire should cap boot can be used for this.
not be extinguished by it because the wicked chemicals
release by it are good conductors of electricity.

Occupational Safety and Health 178 YCT

(vi) To tamper with a running machine is to invite an (v) Before making the job, its drawing should be
accident. So do not stand on the support of a understood very well.
running machine or its parts (such as touch a bolt
etc.)
(vii) If you have to work while standing near a running
machine, then you must put a safety guard on the
running machine, so that there is no fear of
accident.
(viii) Lift the load properly, use the muscles of the legs
not the muscles of the back.

Safety signs- Safety sign warn us about potential danger

and we should never ignore them. These marks can be
identified by their shape and colour-
• The safety signs are of the following types-
(a) Prohibition signs
(b) Machine-tools safety- For the safety of (b) Mandatory signs
machines and tools etc we should pay attention to the (c) Warning signs
following things- (d) Informational signs
(i) All micro meter instruments should be kept oiled (a) Prohibition signs– These circular shaped
from time to time. They must be take care of signals are made by a red border and cross bar and a
especially in the rainy season, because on the black figure on a white background.
equipment get rusted, its subtlety is lost.
• By these signs it is forbidden (Prohibited) to do
(ii) After working with the file for a one-two months, it certain types of work. For example-
should be washed, this makes the file use as longer.
(iii) It any part of any machine get damaged, it should be S.N. Signs Sign's instruction
repaired immediately. 1. By this sign it is forbidden
(iv) Whenever micrometer instruments are used, they to walk on foot.
should be kept in a safe place and separate from any
cutting tools.
(v) For cleaning the sand, you should keep a file card
2. Smoking and naked flame
with you and keep cleaning the iron particles stuck
are prohibited.
in the sand with the file card from time to time.

3. Prohibited to extinguish the

fire with water.

(b) Mandatory signs– Through these signs

(c) General workshop safety- For general protective instructions are given to the worker/artisans.
workshop safety, we should pay attention to the • These symbols are made up of a circle in the shape
following points- of a white symbol on a blue background. Examples
(i) Fire extinguisher and safety equipment should be of this are as follows-
kept ready in workshop always. S.N. Signs Sign's instruction
(ii) Smoking should not be allowed in the workshop. 1. Wear protection for head
(iii) The floor of the workshop should be neat and clean.
Oil etc should never be scattered.
(iv) While making the job, the tool should be adopted for
the measurement of the job according to its 2. Wearing a safety harness
precision; for example, steel rule for rough belt.
measurement and micrometer or vernier callipers for
fine measurement.
Occupational Safety and Health 179 YCT
 3. Wear protection for (d) Informational Symbols– Various types of
breathing. safety related information are given by these signals.
• These signs are square in shape, represented by a
white coloured figure on a green background or a
4. Wear protection for hands. red coloured figure on a white background.

5. Wear protection for feet.

6. Wear protection for hear.

7. Use adjustable guards. 6. Soft Skills– A naturally developed skill in an artisan

that is useful in an emergency is called a soft skill.
• 5'S' Concept of soft skills– The 5'S' Concept is an
combination of japanese words. Under skill training,
(c) Warning signs– Warning is given through these attention should be paid to the following five words
signs. starting with the letter 'S' and they should be put into
• These marks are displayed by making black drawing practice. Such as-
on a triangular yellow background. The warning a. Sort b. Set in order c. Shine
signs are shown in the following table- d. Standardise e. Sustain
S.N. Signs Instruction
1. for risk from fire

2. for risk from electric shock

3. for risk from poison

4. For corrosive substances Note- 5'S' concept is a circular sequence, which rises
to the process of sustainable development.
(a) Sort–
5. for risk from explosion (i) This is the first S of 5'S'
(ii) It excludes those unnecessary items from the work
system which are not necessary from the point of
view of the present production.
6. for risk from overhead (iii) It is also known as Red tagging.
(iv) Organization have many advantages from sorting,
such as- gain of valuable floor area and elimination
7. for risk from General of broken equipment, scarps and excess raw
warning materials.
(b) Set in Order–
(i) This method arranges all the items in proper form so
8. for risk from ionizing that they can be labeled easily.
radiation (ii) This method can be successful only when the first
column of 5'S' is separated from the scope (work
9. for risk from laser beam area) by sorting unnecessary items.
(iii) Painting of surface, setting of lebels, outlining of
work areas and places etc. come under the set in
order method.
Occupational Safety and Health 180 YCT
(c) Shine– 7. Response to Emergencies– Workshop in industrial
(i) This method is related to the cleaning method of the training institutes is such a work area where
work area and all the machines. processes of various nature go on every minutes.
(ii) By working in a clean environment, workers can (a) Power Failure– Electrical power failure is a
easily see and understand the fault in any machine common emergency situation in the workshop. During
and solve it. this, the trainee's reactions should be as follows -
(iii) Organization often establish shine goal assignments, i. Switch off the main switch of the workshop
methods and tool etc before starting the sine pillar. immediately.
(d) Standardise– ii. Try to find out the reason for this emergency.
(i) Under this, a best process is standardized in the field iii. In case of the reason responsible for the emergency
of work. is unusual, restore the power supply only after
(ii) Under this method, the process is standardized proper prevention.
which maintains all the three previous pillars. iv. Maintain patience and self control even in this
adverse situation.
(iii) Three steps are included under this method-
(b) Fire Catching–
(a) Assign job responsibility of 5'S' (sort, set in
i. Find out the cause of the fire.
order, shine).
ii. In this situation inform the fire brigade and higher
(b) Integrating the 5'S' functions as a regular
officials immediately.
function.
iii. Try to cannot the fire immediately by using suitable
(c) Regular checking to maintain the 5'S'.
fire extinguishers available in the workshop.
(e) Sustain–
iv. Never use water if the cause of fire is electricity.
(i) This is the hardest 'S', the aim of which is to
(c) System Failure– System failure is an accidental
maintain the proper methods and procedures.
disturbance generated in the system of a workshop, due
(ii) This method focuses on defining the new present to which its functioning is interrupted and affects the
status and work area standards of the organization. continuity of work. In such a situation, the reactions of
(iii) Without this pillar, the achievements of all the other the trainee should be as follows-
pillars cannot be for longer. There are many tools for i. Try to known the reason yourself by informing the
this pillar, which are as follows- competent authority.
(a) Signs and posters ii. Immediately deactivate the machines and
(b) Newspaper equipments related to the workshop system.
(c) Performance review iii Check the system properly and rectify the fault
(d) Departmental tour. immediately if found.
Exam Pointer
■ Foam type apparatus is used to ■ If there is a fire of wood, cardboard or cloth at any
- Extinguish the fire caused by place, then it is used - Soda acid type device
burning oily substances ■ The full form of BIS is
■ Which tube should be kept in the first aid box for - Bureau of Indian standards
wound healing - Betadine ■ The shape of the surface of the information security
■ Which class comes under fires are caused by wood or sign is - Square
jute - Class A ■ Fire caused by LPG, and gas comes under
■ Name of items used in first aid - Class 'C'
- Dettol, Tincture iodine and Burnol ■ The symbol of the lamp on the wall is -
■ The shape of soda acid fire extinguisher is - Cone
■ What should we use to extinguish fire in case of
■ The danger of electric shock is indicated by -
electricity - Sand or soil
■ CO2 fire extinguishers are used for the purpose of ■ The symbol of a sing way switch is -
- Extinguish electrical fire
■ The shape and colour of the border of the prohibition ■ The danger sign for electrical panel is -
sign is - Circular and red
■ Which quantity of gas is reduced in the fire area by ■ The symbol of choke is–
fire extinguisher - Oxygen
■ Which is used to extinguish the fire caused by
sparking in electric wires
- CTC (carbon tetrachloride) ■ The symbol of no smoking is -
■ Which fire extinguisher should be used to extinguish
the fire caused by LPG gas ■ What type of liquid is filled with air pressure in CTC
- Dry compound extinguisher fire extinguisher - (CBrClF2) and (CCl4)
Occupational Safety and Health 181 YCT
■ For the safety purpose, fuse should be always ■ Which artificial respiration method is adopted when a
connected on the - Phase wire person is suffering from electric shock has blisters on
■ Approximately how many times should the Schaffer his back - Schaffer's method
method of artificial respiration be repeated in a ■ If a patient does not respond well to mouth to mouth
minute - 10 to 12 times resuscitation, the fist aider should
■ Which is necessary to use while working on live - Seek medical attention immediately
electric line - Rubber gloves and insulated tools ■ Which type of fire extinguisher is to be used on
■ The shape of warning signs is - Triangular electrical equipment or installation under fire
■ Which extinguisher is used to extinguish 'B' class fire - Halon type
- Foam extinguisher device ■ Which device can be used to extinguish all types of
■ Which extinguisher is used to extinguish petrol fire fire - CTC fire extinguisher device
- Foam type extinguisher ■ Who can properly operate the machines
■ What type of spraying is done by fire extinguisher - Skilled man labour, skilled engineer
- Liquid, powder and gas ■ Unintentional incident with uncontrollable and sad
■ The full form of ISI is consequences is called - Accident
- Indian Standard Institution ■ The main cause of industrial accident is
■ What color is used for informational signs - Inattention
- Green or white ■ Which important process takes place in the body to
■ Schaffer's method, Sylvester's method and mouth to transport oxygen from the atmosphere to the brain
mouth respiration are the method of and various cells of the body
- Artificial respiration - Respiration and blood circulation
■ As per BIS standard, which code is used for
■ The medical treatment given to the accident victim
earthing system - IS 3043
before the arrival of the doctor is called - First aid
■ The shower of cold water is suitable to extinguish the
■ The effect of electric shock on human body depends
fire of - Wood, cloth and paper
on - Line voltage
■ Which signs are used white symbols on a blue
■ What types of damages can happen to the human
background - Mandatory sign
body due to electric shock
■ Information security sign is - - Blisters on a particulate organ, burning of skin,
cardiac arrest and death, obstruction
■ To rescue the person who came in contact with
in breathing and unconsciousness
electricity
■ Which fire extinguishers should not be used for
- The main switched should be switched off
■ While changing the fuse wire, it is mandatory for electrical fires - Foam type
safety - To switch off the main switched ■ ISO stands for
■ Electrician's shoes should be made of - Rubber - International organization for standardization
■ Which safety equipment comes under the category of ■ Which part of the body should bear the maximum
PPE - Gloves, goggles and safety belt weight while lifting heavy objects in the workshop
■ The best way of avoiding accident is - On feet
- Observing safety rules related ■ Which extinguisher is used for the fire caused due to
to job, machine and workplace oil, petrol or electric faults
■ The failure of electrical power in the workshop is - CTC (carbon tetrachloride)
usually due to - Emergency situation ■ Which class of fire is used to extinguish CO2 fire
■ In which type of safety sign are made of red border extinguisher - Class B and class C
and red cross bar - Prohibited sign ■ What can be used to neutralize acid waste in an waste
■ In examples of safety symbols, examples of water treatment plant - Alkali
mandatory symbol is - Wearing head protection ■ The symbol of laser beam is -
■ What should be used for cleaning the oily surface
- Sawdust ■ What should be available for fire extinguishing in
■ How do you remove a person stuck to an electric electrical workshops
supply wire - By rubber gloves or dry wood - Fire extinguishers should be available,
■ When the current is at a very low level, the effect of buckets filled with sand should be available and
electric shock on a person will be
there should be an overhead tank
- Slightly burn at the contact place
filled with water for water arrangement.
■ Which drink should not be given to a person having
tremors - Tea, water and coffee ■ The first aid treatment for snake bite is
■ In which method, the patient is laid on their back and - To tie a cloth on the bite area and cut the
a pillow is placed under the back - Sylvester method bite area to let the blood out.
Occupational Safety and Health 182 YCT
■ Which type of protective equipment used to protect
head - Hard hats, Helmets
■ What to wear for the protection of the feet
- Leather shoe
■ What are we use for the protection of the eye
- Goggles, face shields and Glasses
■ What are use for protection of the body - Apron
■ Properly equipped and should be kept at an easily
■ When grinding, works man always
accessible place - First aid Box
- Stand on the side of wheel
■ Carbon terminal chlorine, carbon tetra chloride and
■ What is the range of electric current causes a heart
Chloro tetrachloride are full name of - C.T.C.
condition which results in instant death
■ The category of fire involving electric wires,
- 50-100mA
equipment and other metallic materials is - 'D' class
■ According to the factories Act 1948, part 23 which is
■ What is the best way to extinguish fire, if a person's
not a dangerous machine - Grinding machine
clothes catch fire - Cover with a wollen blanket
■ When doing electrical work, a notice board should be
■ The simplest method of artificial respiration is
used as a safety standard for - Most dangerous
- Method Sylvester's
■ In class-A fire, the causes of fire is - Wood
■ OSHA was created to - To reduce hazards
■ According to the definition of "week" under the
■ What is OSHA form 300 and when it needs to be
factory Act 1948, it is a Period of 7 days beginning at
posted-
midnight on - Saturday
Summary of previous years work related
■ Indian Boiler Act, 1923 is applicable to
injuries and diseases February 1st
- Boilers more than 100 liters capacity.
■ The physical occupational hazards to which the
■ Which tactics are used to Promote safety
welder is exposed to are
- Writing slogans
- Infrared radiation,
■ Fire is classified as - Four types (A, B, C, D)
visible radiation, noise.
■ A fire caused by liquids are classified as
■ Decibel (dB) is a unit used to measure
- Class 'B' fire
- Sound loudness.
■ Which type of fire is used to extinguish the soda acid
■ The threshold concentration of sulphur dioxide in any
extinguisher - Class 'A'
industrial activity should not be permitted beyond -
■ What should be done if there is darkness due to 5 ppm
power failure at the work place ■ Which of the following is used as antiknock
- Do not create panic, arrange alternative compound in gasoline. - Tetraethyl lead
lighting and use stairs
■ The submicron particulates (Size 0.5 to 5µn)
■ While using hammer, keep an eye on - The job
associated with smoke and fumes are very effectively
■ For respiratory protection, we use removed by - Venturi Scrubber
- Filter respirators
■ The minimum size of smoke particle is - 0.5µm
■ Which chemicals are used in foam type fire ■ The major contributor of carbon monoxide is
extinguisher - Na2CO3 + AlSO4 - Motor Vehicle
■ Symbol shown in figure represents - Prohibition sign
■ The main function of automobile catalytic converter
is to control emissions of
- Carbon Monoxide and nitrogen dioxide
■ One of the gas involved in production of carboxy
hemoglobin is - CO
■ One of the gas that easily oxidize paints, dyes, textile
fibers is - Ozone
■ Wet body has resistance - Less
■ The full name of CCl4 is - Carbon Tetrachloride
■ The meaning of 5(S) is
- Sort, set, shine, standardize distance, Sustain.
■ Symbol shown in figure represents - Warning sign ■ As per BIS standard, which code is used for
electrical wiring installation - IS -732
■ Which of the following signals is a white signal on a
blue background in the shape of a circle is
- Mandatory signal
■ Symbol shown in figure represents - Mandatory sign ■ BIS standard were set in the year - 1986
Occupational Safety and Health 183 YCT
 PREVIOUS YEAR QUESTION
1. ____is a penicillin antibiotic that fights bacteria. Ans : (c) Asbestos particles can cause lung cancer and
(a) Ibuprofen (b) Clonazepam respiratory diseases. All forms of asbestos are
(c) Atorvastatin (d) Amoxicillin carcinogenic to humans. Exposure to asbestos can
RRB ALP & Tech. 08.02.2019 Shift-I cause cancer of lungs and ovaries and cancer of the
Ans : (d) : Amoxicillin is used in the treatment of pleural and peritoneal lining.
bacterial infections. It is a drug belonging to the 6. Vitamin B1 is also known as_______.
penicillin type antibiotic group of drugs. This (a) Niacin (b) Riboflavin
medication is used along with amoxicillin in the (c) Ascorbic acid (d) Thiamine
treatment of bronchitic pneumonia and infections of RRB ALP & Tech. 08.02.2019 Shift-I
ears, nose, throat, skin or urinary tract.
Ans : (d) : Vitamins and their chemical names-
2. _________ was discovered by the Scottish
Vitamin Chemical name
physician Daniel Rutherford in 1772.
Vitamin B1 - Thiamine
(a) Nitrogen (b) Hydrogen
Vitamin B2 - Riboflavin
(c) Chlorine (d) Helium
Vitamin B3 - Pantothenic acid
RRB ALP & Tech. 21.01.2019 Shift-II
Vitamin B6 - Pyridoxine
Ans : (a) : Nitrogen was discovered by the Scottish
physician Daniel Rutherford in 1772. Nitrogen is the 7. A common drug in a first aid box is Ibuprofen.
chemical element with the symbol 'N' and atomic When should Ibuprofen be taken?
number 7. Nitrogen is the fifth most abundant element (a) To aid in clotting of blood
in the universe, making up 78% of Earth's air. (b) To bring relief from asthma
Chemical element Discoverer (c) To ease indigestion and heartburn
Hydrogen - Henry Cavendish (d) To treat pain, fever and inflammation
Chlorine - Carl Wilhelm Scheele RRB ALP & Tech. 21.01.2019 Shift-II
Helium - Pierre Jules, Norman Ans : (d) : Ibuprofen medicine should be taken to treat
Lockyer, William Ramsay pain, fever and inflammation. It is a common medicine
3. Antihistamines are found in some first-aid in the first aid box. It is on the world health
boxes. When should these drugs be taken? organization's list of essential medicines, which are the
(a) To ease indigestion and heartburn safest and most effective medicines required in the a
(b) To ease the symptoms of hay fever and other health system.
allergies 8. Which vitamin is needed for proper clotting of
(c) To bring relief from asthma blood ?
(d) To aid in clotting of blood (a) Vitamin A (b) Vitamin E
RRB ALP & Tech. 23.01.2019 Shift-I (c) Vitamin D (d) Vitamin K
Ans : (b) Antihistamines drugs are used to ease the RRB ALP & Tech. 21.01.2019 Shift-I
symptoms of hay fever, conjunctivitis, other allergies Ans : (d) : Vitamin K is required for proper clotting of
and to treat insect bites or stings. blood. Due to its deficiency blood clot does not form
4. Paracetamol is found in first-aid boxes. due to injury on the body, which can also lead to death
When/why should these drugs be taken? of the person due to excessive bleeding. Phylloquinone
(a) To ease mild pain and reduce high is the chemical name of vitamin 'K'. It is a fat soluble
temperature (fever.) vitamin. Its main sources are eggs, liver products, green
(b) To ease the symptoms of hay fever and other leafy vegetables, tomato, cabbage, soybean etc.
allergies. 9. Raising the head to straighten the neck is called
(c) To bring relief from asthma ________.
(d) To ease indigestion and heartburn. (a) chin tuck (b) wrist stretch
RRB ALP & Tech. 23.01.2019 Shift-II (c) pectoral stretch (d) finger fan
Ans : (a) Paracetamol medicines should be taken to RRB ALP & Tech. 22.01.2019 Shift-I
ease mild pain and reduce high temperature (fever). Ans : (a) Chin tuck are typically one of the key
5. Which hazardous substance can cause lung exercises recommended for keeping the head aligned
cancer? above the spine, rather than drifting forward into poor
(a) Arsenic (b) Herbicides posture. Only the chin and upper neck are the focus of a
(c) Asbestos particles (d) Benzene vapours chin tuck. Therefore, we can say that raising the head to
RRB ALP & Tech. 23.01.2019 Shift-I straighten the neck is called chin tuck.

Occupational Safety and Health 184 YCT

10. If the magnitude of current passing through Ans: (c) Informative signs are rectangular in shape,
the human body is as follows, then shock will represented by a white shape on a green background or
not be felt- a red shaped on a white background.
(CRPF Constable Tradesman Kathgodam An informative sign is a sign that is used to inform
Electrician 07-04-2013) people of the purpose of an object, gives them
instruction on the use of something.
(a) less than 1 mA (b) 10 to 40 mA
16. Which of the following fire extinguishers must
(c) 8 to 15 mA (d) 1 to 8 mA not be used for fires generated due to electricity?
Ans : (a) If the magnitude of current passing through (UPRVUNL-TG2 Instrumental-2015)
the human body is less than 1 mA, then shock is not (a) Carbon tetrachloride type
felt. The resistance of human body is approximately (b) Foam type
1000Ω. (c) Sand filled type
11. The effect of electric shock on the human body (d) Carbon dioxide
depends on the following- Ans : (b) Foam type extinguisher must not be used for
(JMRC-Electrician 2016), (IOF 2015) fires generated due to electricity.
(a) Line voltage • Foam type extinguishers are the most effective and
(b) Line current safe extinguisher to use on fire involving flammable
(c) Line current and voltage liquids and solid combustible.
(d) All of the above • The foam type extinguisher is mostly water based
with a foaming agent that generates foam on the surface
Ans : (a) The effect of electric shock on the human
of the fuel, thereby cutting the air supply stopping the
body depends on the line voltage. fire.
The supply of upto 90 voltage can give a reverse shock
to the human body and as the line voltage is increased 17. ISO stands for
then the shock becomes more effective. (UPRVUNL-TG2 Instrumental-2015)
(a) Indian Standard Organization
12. Which of the following are the harms that can
occur to a person due to electric shock- (b) International organization for standardization
(ESIC electrician-2016) (c) International Science organization
(a) Blisters on a particular body part or burning (d) Indian Science Organization
of flesh Ans : (b) ISO stands for international organization for
(b) Heart failure and death standardization. It was founded on 23 February 1947.
(c) Obstruction in breathing and The organization develops and publishes
unconsciousness standardization in all technical and non technical fields
rather than electrical and electronic engineering which
(d) All of the above is handled by the IEC. It is headquatered in Geneva,
Ans : (d) Obstruction in breathing and unconsciousness, Switzerland and works in 167 countries as of 2023.
cardiac arrest and death, blisters on any particular body 18. In order to extinguish electrical fire which kind
or burning of flesh, all these can happen to a person due of fire extinguisher should be used?
to electric shock.
(UPPCL-TG2-Electrical-2015)
13. Which of the following can be used to (a) B type (b) A type
extinguish an electric fire? (c) A and B type (d) C type
(UPPCL-2016, TG2 Exam Date : 26-06-2016)
Ans : (d) According to NFPA (National Fire
(a) Water (b) Carbon powder
Protection Association),
(c) Dry sand (d) None of these
C-class fire- This includes the fire in the windings of
Ans : (c) Dry sand, CO2 type extinguisher and CTC
machines like motors generators, transformers,
extinguisher are used to extinguish the fire caused by
electric fire. domestic and power wiring, coils, wire insulation,
control panel etc. which is generated by electric
14. Which of the following is the cause of sparking
sparking.
in an electrical appliance?
It is controlled by the following extinguisher method-
(UPPCL-2016, TG2 Exam Date : 26-06-2016) (i) Carbon tetra-chloride fire cylinder
(a) Loose connection (b) Faulty appliance
(ii) Carbon dioxides gas fire cylinder.
(c) Short circuit (d) Open circuit
19. While lifting heavy objects in a workshop,
Ans : (a) Loose connection is the cause of sparking in a maximum load should be on which part of the
electrical appliance. Due to which the contacts of the body ?
equipment are destroyed.
(UPPCL-TG-2 Electrician-2015)
15. The background colour of informative sign is (a) on the back (b) on the feet
(UPRVUNL-TG2 Instrumental-2015) (c) on the chest (d) on the shoulders
(a) Red (b) Blue Ans : (b) While lifting heavy objects in a workshop,
(c) Green (d) Yellow maximum load should be on the feet of the body.
Occupational Safety and Health 185 YCT
20. Which one of the following fire extinguishers is (a) Fuse
suitable for extinguishing on electrical fire? (b) Fault
(UPPCL-TG-2 Electrician-2015) (c) Danger of Electric Shock
(a) Water extinguisher (d) Danger on Electric panel
(b) Soda acid extinguisher Ans : (c) The given sign/symbol is used for danger of
(c) Halon extinguisher electric shock.
(d) Foam extinguisher 26. For which of the following classes of fire CO2
Ans : (c) Halon extinguisher is suitable for Extinguisher are used ?
extinguishing an electrical fire. It is also known as (LMRC Maintainer Electrical Exam 2016),
CTC fire extinguisher. (IOF 2013)
21. Electrical fires should be extinguished by the (a) Class A & Class B (b) Class A & Class D
use of (c) Class A & Class C (d) Class B & Class C
(UPPCL-TG-2 Electrical-2014) Ans : (d) CO2 fire extinguisher is used to extinguish
(a) water class B and class C fires.
(b) carbon tetra chloride fire extinguisher Class B fires involve flammable liquids such as
gasoline, oil, grease or solvents. The CO2 in the
(c) foam type fire extinguisher extinguisher displaces the oxygen surrounding the fire,
(d) any of the fire extinguisher in 'b' and 'c' effectively suppressing the combustion process.
Ans : (b) Electrical fires should be extinguished by the Class C fires involve energized electrical equipment
use of carbon tetra chloride fire extinguisher. such as appliances, wiring or circuit breakers. CO2 fire
22. Which of the following is not a type of safety in extinguishers are non-conductive and can safely be
Occupational Safety? used on live electrical fires.
(UPRVUNL-TG-2 Electrical-2015) 27. Which type of fire extinguisher is suited for
(a) Machine Safety (b) Body Safety extinguishing electrical fire ?
(c) Work Safety (d) Road Safety (ISRO Technician Electrical 27.11.2016)
(a) Soda–Acid Fire Extinguisher
Ans : (d) Road safety is not a type of safety in
(b) Carbon–Dioxide Fire Extinguisher
occupational safety. Machine safety, body safety and
work safety, these are comes under occupational (c) Foam Type Fire Extinguisher
safety. (d) Water
Ans : (b) CO2, sand (SiO2) and carbon tetra chloride are
23. A tube of.............is kept in a first aid box for
used to extinguish electrical fire.
healing of wounds.
(UPRVUNL-TG-2 Electrical-2015), (IOF 2014) 28. Water break test is used to:
(a) Soframycin (b) Penicillin (ISRO Technician Electroplating 27.11.2016)
(a) Measure plated thickness
(c) Betadine (d) Fair and Lovely
(b) Verify Uniformily of coating
Ans : (c) A tube of betadine is kept in a first aid box (c) Measure electrolyte Concentration
for healing of wounds.
(d) Verify Cleanliness of surfaces
• Soframycin is used in pain relief.
Ans : (d) Water break test is used to verify cleanliness
• Fair and lovely is used for removing blemishes and of surfaces.
spots on the skin.
29. In an effluent treatment plant, acid waste is
• Penicillin is used for skin diseases. neutralized by combining it with:
24. If the fire is caused due to oil, petrol or electric (ISRO Technician Electroplating 27.11.2016)
faults, the type of extinguisher used is: (a) Alkali (b) Water
(UPRVUNL-TG-2 Electrical-2015) (c) Organic solvent (d) salt
(a) Soda acid type (b) Foam type Ans : (a) In an effluent treatment plant, acid waste is
(c) C.T.C (d) Carbon dioxide neutralized by combining it with alkali.
Ans : (c) If the fire is caused due to oil, petrol or ETP (Effluent Treatment Plant) is a process design for
electric faults then CTC fire extinguisher is used. This treating the industrial waste water for its reuse or safe
type of fire extinguisher is generally used to disposal to the environment.
extinguish all types of fires, but is more suitable and Acid or alkali is added to the effluent to increase or
safe for electrical fires. decrease the pH.
25. The following figure is a symbol for 30. The given sign depicts warning from..............
(UPPCL Technical Grade-II Electrical 11.11.2016)

(UPRVUNL-TG-2 Electrical-2015)
Occupational Safety and Health 186 YCT
 (a) Ionizing radiation (b) Risk of exposion 36. The simplest method of artificial respiration is-
(c) Laser beam (d) Electric shock (R.R.B. Ajmer (L.P.) 2004)
Ans : (c) The given sign depicts warning from laser beam. (a) Silvestre method
31. The background colour of Informative sign is (b) Shaffer's method
............and is...............is shape. (c) Mouth to mouth method
(UPPCL Technical Grade-II Electrical 11.11.2016) (d) None of the above
(a) greenk, circuler (b) white, circuler Ans : (c) The simplest method of artificial respiration is
(c) green, square (d) white, triangular to give mouth to mouth breathing, make the victim lie
on his back and clean the victim's mouth thoroughly.
Ans : (c) The background colour of informative sign is
Now, place a fine cloth on his open mouth and cover his
green and square in shape.
nose with one hand and blow air forcefully through
32. Which of the following signs have both border your mouth.
and a cross in between, painted with red colour?
37. To rescue a person who has come in contact with
(UPPCL Technical Grade-II Electrical 11.11.2016) electricity-
(a) Prohibitive sign (b) Mandarory sign (VIZAAG Steel, Electrician)
(c) informat sign (d) Warning sign (a) The main switch should be turned off
Ans : (a) Prohibitive sign have both border and cross in (b) The wire should be cut with a knife
between, painted with red colour. The background of (c) The victim should be pushed and separated
the prohibitive sign is white. from the line
33. After an electric shock, in which of the (d) Any one of the above methods can be
following methods of artificial respiration, the adopted
affected person is made to lie on the ground Ans : (a) To get rid of the person coming in contact
keeping the chest downwards? with electricity, the main switch should be switched off
(UPPCL Technical Grade-II Electrical 11.11.2016) and it should careful that while getting rid of the
(a) Shaffer's method electrical contact, the victim should not fall on the
(b) Silvester method ground due to shock and should not get hurt.
(c) Mouth to mouth method 38. For extinguishing fire in electrical workshops-
(d) Use of artificial respirator (CRPF constable Tradesman Himachal Pradesh
Electrician 30-12-2012)
Ans : (a) After an electric shock, in the Shaffer's
(a) Fire extinguishes equipment should be
method of artificial respiration, the affected person is
available
made to lie on the ground keeping the chest downwards.
(b) Buckets filled with sand should be available
34. Red colored border and red cross bar are used (c) There should be an overhead tank filled with
in which type of 'safety signal' ? water for arrangement
(R.R.B. Ajmer (L.P.) 2004) (d) All the above three things should be available
(a) Prohibitive (b) Mandatory Ans : (d) For extinguishing fire in electrical
(c) Cautionary (d) Informative workshops-
Ans : (a) Red colored border and red cross bar are used (i) Fire extinguishers equipment should be available
in prohibitive type safety signal. Prohibitive signs are (ii) Buckets filled with sand should be available
in the shape of circle. These signs are formed by a red (iii) There should be an overhead tank filled with water for
border and cross bar and a black figure on a white water supply.
background. Special type of work is forbidden by them. 39. What type of fire extinguishers are used in
35. Which fire extinguisher is used to extinguish the establishment containing electrical equipment
fire in electrical wires? and such fires?
(R.R.B. Ranchi (L.P.) 2014) (CRPF Overseer Electrician-2015)
(a) water type extinguisher (a) Foam type
(b) foam type extinguisher (b) Halon type
(c) carbon tetra chloride type extinguisher (c) Gas cartridge water filled type
(d) spray of water (d) Pressurized water type
Ans : (c) To extinguish the fire in electrical wires, a Ans : (b) Halon type fire extinguishers are used in
device containing carbon tetra chloride is used. On installation involving electrical equipment and similar
pressing the lever of this type of device, spraying of air fires. There are mainly four types of fire extinguishers-
mixed liquid starts. Generally, this device can be used (i) Soda acid fire extinguisher
to extinguish all types of fires. This liquid covers the (ii) Foam fire extinguisher
burning object and extinguishes the fire instantly by (iii) Carbon dioxide fire extinguisher
cutting off its oxygen supply. (iv) Carbon tetra chloride fire extinguisher equipments

Occupational Safety and Health 187 YCT

40. Which type of fire extinguisher is used to Ans: (d) Overalls, apron and gloves should be worn to
extinguish electrical fire? protect the body.
(UPRVUNL TG-II Electrician–2016) 47. While grinding, we always-
(a) Halon fire extinguisher (HAL Fitter, 2015)
(b) Stored pressure, water filled fire extinguisher (a) stand in front of the wheel
(c) Water filled gas cartridge fire extinguisher (b) stand on the side of the wheel
(d) Foam filled fire extinguisher (c) wear goggles
Ans : (a) Halon fire extinguisher is used to extinguish (d) both (b) and (c)
electrical fire.
Ans : (d) Always stand on the side of the wheel while
41. The first Aid in case of snake bite is.............. grinding with a grinder at the work site as the sparks
(ISRO Technician Plumber 27-11-2016) coming out of the wheel can harm you and wear eye
(a) Pour water on wound glasses.
(b) Put anti septic on wound 48. Which of the following is not being included in
(c) Tie cloth around wound and cut the wound to the hand book?
bleed the blood (UPRVUNL Technician Grade II Fitter 22-09-2015)
(d) Rub the wound (a) Fundamental information's
Ans : (c) The first aid in case of snake bite- First, the (b) Directional details
snake bitten area should be tied with a rope or cloth and (c) General defects
then the wound should be bleed the blood. (d) Factories act
42. If a patient does not perform mouth breathing Ans : (d) The hand book contains fundamental
correctly, then first aid should be done as information, directional details and general defects and
follows- does not contain factories act.
(BHEL Hyderabad Fitter, 2014)
49. Match the following given lists :
(a) Seek medical help immediately
(UPRVUNL Technician Grade II Fitter 22-09-2015)
(b) See broken bones
(c) Keep the body warm with blanket List-I List-II
(d) Cheek pulse and eye sight (Type of fire) (Fuel)
Ans : (a) If a patient does not perform mouth breathing A. Class A fire 1. Gas & liquefied gas
properly, then first aid should be seek medical help B. Class B fire 2. Wood
immediately. C. Class C fire 3. Metalsb
43. To protect the head, we use D. Class D fire 4. Flammable liquids
(IOF Fitter, 2016) (a) A–2, B–4, C–1, D–3
(a) hard hats (b) helmets (b) A–1, B–2, C–3, D–4
(c) caps (c) A–3, B–4, C–1, D–2
(d) both (a) and (b) above (d) A–3, B–4, C–2, D–1
Ans : (d) To protect the head, we use hard hats and Ans : (a) Type of fire Fuel
helmets, which covers the entire head and protects the
A. Class A fire 2. Wood
head from injury.
B. Class B fire 4. Flammable liquids
44. What do you wear to protect your feet?
C. Class C fire 1. Gas and liquefied gas
(RRB Gorakhpur ALP, 21.10.2001)
(a) Slippers (b) Canvas shoe D. Class D fire 3. Metals
(c) Leather shoe (d) All of the above 50. What is the range of electric current causes a
Ans : (c) To protect the feet leather shoes should be heart condition which results in instant death?
wear while working in the workshop, which prevents (UPRVUNL Technician Grade II Fitter 22-09-2015)
the feet from being pricked. (a) 10-20 mA (b) 50-100 mA
45. To protect eyes, we use- (c) 100-110 mA (d) 20-50 mA
(IOF Fitter, 2015) Ans : (b) The range of electric current causes a heart
(a) Goggles (b) Glasses condition which results in instant death is 50 to 100
(c) Face Shields (d) All of the above mA.
Ans : (d) For the safety of the eyes goggles, glasses and 51. According to the factories act 1948, section 23.
face shields should be worn while working in the Which machine is not a dangerous machine?
workshop which keeps the eyes safe. (UPRVUNL Technician Grade II Fitter 22-09-2015)
46. To protect body, we use- (a) Circular saw
(CRPF Constable Tradesman, 2016) (b) Milling machine used in metal trades
(a) Overalls (b) Gloves (c) Power press other then hydraulic press
(c) Appron (d) All of the above (d) Grinding machine
Occupational Safety and Health 188 YCT
Ans: (d) According to the factories act 1948, section 57. Which of the following helps in accident control?
23, grinding machine is not a dangerous machine. (RRB Patna ALP, 11.11.2001)
52. Type of fuel for fire of Class 'A' type: (a) Automatic safety guard
(SRO Technician-B Carpenter 27-11-2016) (b) Interlock safety guard
(a) Gas and liquefied Gas (c) trip safety guard
(b) Flammable liquid & liquified solids (d) All of these
(c) Wood, cloth, Paper Ans : (d) The following measures are taken for safety
(d) Fires in Electrical equipment and metal fires in industrial units-
(i) Automatic safety guard
Ans : (c) The fuel for the fire is selected is follows-
(ii) Interlock safety guard
• Class A type consists of cloth paper, wood, plastic
(iii) Trip safety guard.
etc.
• Class B type consists of oil, petrol etc. 58. Which of the followings, leads to industrial
hazards and causes accidents?
• Class C type consists of inflammable gases such as
(IOF Fitter, 2015)
propane, butane, methane etc.
(a) Noise and vibrations
• Class D type consist of metals, aluminium, (b) Poor lighting and Poor ventilation
magnesium, titanium and electric fire etc.
(c) Heat and Humidity
53. Types of fire extinguishers for Class 'A' Fire: (d) All of these
(ISRO Technician-B Carpenter 27-11-2016) Ans: (d) Industrial hazards and accidents are caused
(a) Water filled extinguishers by-
(b) Foam or Dry powder or CO2 (i) Noise and vibration
(c) Special powders (ii) Poor light and poor air circulation
(d) Halon, Carbon dioxide, dry powder and (iii) Heat and humidity
vaporizing liquid (CTC) (iv) Disinterest
Ans : (a) Extinguishers for class A fires is water filled (v) Unsafe clothing
extinguishers. (vi) Haste
54. Which sign board should be used as a safety 59. Indian Boiler Act, 1923 is applicable to
standard while doing electrical work? (MAZAGON DOCK Ltd. Fitter, 2013)
(Noida Metro Maintainer Fitter 2017) (a) all boilers
(a) Do not come in contact with extreme heat (b) boilers more than 100 litres capacity
(b) Extremely dangerous (c) boilers more than 1000 litres capacity
(c) Strictly prohibited area (d) None of the above
(d) Do not touch hot Ans : (b) Indian boiler act, 1923 is applicable to boilers
Ans : (b) While doing electrical work, use extremely more than 100 litres capacity.
dangerous signboard as a safety standard. 60. Which of the following safety measures is used
55. Class-A fire consists of fire due to: to promote the safety?
(ISRO Grinder 27-11-2016) (MES Fitter Tradesman, 2015)
(a) Wood (b) Oil (a) Excessive fine (b) Writing slogans
(c) Transformer (d) Chemical (c) Stopping the work (d) All of these
Ans : (a) Ans : (b) 'Writing slogans' safety measures is used to
promote the safety. Some following slogans are-
Class Reason
(i) "Do not talk while working, other wise you will
A Class Wood, paper, leaves meet by accidents"
B Class Flammable liquid such as oil, petrol etc (ii) There are three enemies of life- "negligence,
C Class Includes propane, methane etc intoxicate, pollution"
D Class Magnesium, titanium metal flame and (iii) "Do not leave it as luck, do not break the safety
electrical fire rules".
56. According to the definition of ''week'' under 61. Which of the following is true if
the Factory Act, 1948, it is a period of 7 days environmentally sound products are made
beginning at midnight on through efficient processes?
(HAL Fitter, 2015) (RRB Chennai/Bangalore ALP, 27.10.2002)
(a) It is unprofitable,as long as recyclable
(a) Sunday (b) Monday
materials prices are soft
(c) Saturday (d) Friday (b) It is known as lean manufacturing
Ans : (b) According to the definition of "week" under (c) It can still be profitable
the factory act 1948, it is a period of 7 days beginning (d) It is easier for repetitive processes than for
at midnight on Monday. product-focussed processes
Occupational Safety and Health 189 YCT
 Ans: (c) If environmentally sound product are made Ans : (a) A fire caused by gas is extinguished by dry
through efficient processes then it can be profitable. powder fire extinguisher. These are also store in
62. In how many of the following categories is fire pressure type or gas cartridge type. These are similar to
classified- water filled, the only difference is the nozzle. They are
(IOF Fitter, 2016) used to extinguish class 'B' fire i.e fire caused by gases.
(a) Two (b) One
(c) Four (d) Three
Ans : (c) There are four classes of fire which are A, B,
C and D. 'A' category of fire includes carbonaceous, 'B'
category of fire include oily substances, 'C' category of
fire include gaseous fire and 'D' category is electrical
fire.
63. In class 'A' the fire caused by-
(VIZAAG Steel Fitter, 2015) 68. CO2 is used to extinguish which types of fires-
(a) liquids (b) wood, paper (RRB Guwahati ALP, 22.01.2006)
(c) gas (d) electricity (a) Class 'A' (b) Class 'C'
Ans : (b) Class 'A' is a carbonaceous fire that is the (c) Class 'D' (d) Class 'B'
materials that made of wood, paper, cloth, rubber and Ans : (c) Dry chemical extinguisher is used on electric
some plastics. Pressurized water, foam or multi purpose fire. Usually it is plunger type. In this, sodium
(ABC) dry chemical fire extinguishers are used to bicarbonate powder is expelled through carbon dioxide
extinguish the fire. (CO2) or nitrogen gas. This is used to extinguish class
64. In class 'B', the fire caused by- 'D' types of fires.
(RRB Ranchi ALP, 19.01.2003) 69. Foam extinguisher is used to extinguish which
(a) gas (b) electricity type of fire?
(c) oily substance (NTPC Fitter, 2014)
(d) wood and paper etc (a) Class 'B' (b) Class 'D'
Ans : (c) Oily substance (fire) come in class 'B' which (c) Class 'A' (d) Class 'C'
are as follows such as gasoline, kerosene, paint thinner Ans : (a) Foam extinguisher- This type of extinguisher
etc.To extinguish class 'B' fires, flammable liquids are is used to extinguish oil fire. This fire comes in class
extinguished by removing oxygen from the fire. In this 'B'. It contains soda bicarbonate solution in the outer
way dangerous parts can be prevented from reaching container and aluminum sulphate solution in the inner
the ignition point. container a brown colored hand of about 100 mm size is
65. In class D, fire caused by- made on its body.
(MES Fitter Tradesman, 2015) 70. Which type of fire is used to extinguish soda
(a) electricity (b) wood and paper acid extinguisher-
(c) gas (d) oily substance (RRB Ajmer ALP, 23.05.2004)
Ans : (a) Class 'D' is a fire caused by electricity for (a) Class 'D' (b) Class 'C'
example, appliances, switches, electrical boxes or (c) Class 'B' (d) Class 'A'
power tools etc. Ans : (d) Soda acid extinguisher- It is used to
To extinguish this fire CTC fire extinguisher is used. extinguish carbonaceous fire. It contains class 'A' fire.
66. Electrical fire is extinguished by 71. What should be done in case of fire in the
(NTPC Fitter, 2014) workshop-
(a) Water (Sail Bokaro Steel Plant 2016)
(b) Dry powder extinguisher (a) Watch quietly
(c) Soda acid extinguisher (b) Try to get out immediately
(d) CTC fire extinguisher (c) Turn off the main power switch immediately
Ans : (d) CTC fire extinguisher- This fire extinguisher (d) Inform the fire brigade immediately
is filled with carbon tetra chloride and bromochloro di- Ans : (c) In case of fire in the workshop, the main
fluoro methane. It is used to extinguish electrical fires. electric switch should be turned off immediately after
Because its chemicals are electrical insulators, the gas is that one should go out and inform the fire brigade
also harmful. immediately.
67. A fire caused by gas is extinguished by which 72. If there is darkness at the work place due to
of the followings - power failure, then what should be done-
(IOF Fitter, 2014) (IOF Fitter, 2013)
(a) Dry powder fire extinguisher (a) do not panic
(b) CTC fire extinguisher (b) provide alternative lighting
(c) Water (c) use the stairs to get out
(d) All three of the above. (d) All of the above
Occupational Safety and Health 190 YCT
Ans: (d) If there is darkness at the work place due to 80. On what fires is used to soda acid fire
power failure, one should not get panic, find the extinguisher?
arrangements of alternate lighting and use the stairs to (Sail Bokaro Steel Plant 2016)
get out. (a) Wood's fire (b) Petrol fire
73. While using a hammer, you should keep an eye (c) Electrical fire (d) None of these
on- Ans : (a) Soda Acid Extiguisher- It is used to
(RRB Allahabad ALP, 09.12.2007) extinguish carbonaceous fire (such as fire caused by
(a) Chisel head (b) Job wood, cloth and other solid flammable materials). Fire
(c) Hammer (d) None of the above caused by electricity should not be extinguished by it,
Ans : (b) While using a hammer, you should keep an because the chemicals released by it are good
eye on the job only then you can do the right things on conductors of electricity.
the job.
81. What is category 'B' fire?
74. What is used for respiratory protection- (IOF Fitter, 2015)
(IOF Fitter, 2013) (a) Fire in wood, cotton, jute etc
(a) Exhaust Fan (b) Ceiling Fan
(b) Fire in oil, petrol etc
(c) Filter respirators (d) None of the above
(c) LPG gas fire
Ans : (c) Artificial respiration that is filter respirator
(d) Fire in metallic materials
should be used for respiratory protection.
75. Which of the following is not a cause of Ans : (b) Class 'A' fire is involving in wood, paper and
accident - (RRB Chandigarh ALP, 25.05.2003) cloth etc.
(a) inattention to danger • Class 'B' fire is caused by oil, petrol etc.
(b) Negligence • Class 'C' fire is caused by gas.
(c) Respect for safety • Class 'D' fire is involving involving materials and
(d) Wrong use of equipment electricity.
Ans : (c) Accidents in workshop can be caused by 82. Match the following given lists :
inattention to danger, negligence and wrong use of (UPRVUNL Technician Grade II Fitter 22-09-2015)
equipment, but when safety is respected then accidents
COLOUR SYMBOL TYPE
do not occur.
76. Which fire extinguisher is used to extinguish A. Red 1. Warning
the fire of oily substances? (IOF Fitter, 2014) B. Yellow 2. Mandatory
(a) Foam (b) Soda acid C. Blue 3. Prohibition
(c) CTC (d) None of the above D. Green 4. Emergency escape
Ans : (a) Foam type extinguisher is used to extinguish (a) A–3, B–1, C–2, D–4
the fire or oily substances.
(b) A–1, B–2, C–4, D–3
77. Which fire extinguishers would be used to (c) A–2, B–3, C–4, D–1
extinguish the electrical fire?
(d) A–1, B–2, C–3, D–4
(RRB Mumbai ALP, 05.06.2005)
(a) Soda acid (b) Foam type Ans : (a) Colour Symbol type
(c) CTC (d) None of the above A. Red 3 Prohibition
Ans : (c) CTC fire extinguishers is used to extinguish B. Yellow 1 Warning
the electrical fire. C. Blue 2 Mandatory
78. What chemicals are used in foam type fire D. Green 4 Emergency escape
extinguishers? 83. Which of these symbol is used for showing
(Sail Bokaro Steel Plant 2016) toxic hazard–
(a) Na2CO3 + AlSO4 (b) AISO4 + NHCO3 (UPRVUNL Technician Grade II Fitter 22-09-2015)
(c) NaOH + HCl (d) None of the above
Ans: (a) Na2CO3 + AlSO4 chemicals are used in foam type
fire extinguishers
79. Where are dry chemical fire extinguishers
used? (RRB Gorakhpur ALP, 12.10.2003)
(a) Electrical fire (b) Oily fire
(c) Wood's fire (d) None of the above
Ans : (a) Dry chemical fire extinguishers are used for
electrical fires. In this, sodium bicarbonate powder Ans : (b) Danger from toxic hazard is shown by the
along with carbon dioxide or nitrogen gas is spray on symbol shown in option 'b'. Many workers become
the fire. victims of drug addiction and sometimes they go to

Occupational Safety and Health 191 YCT

 factory in an intoxicated state. Such workers not only
become victims of accidents but can also be a danger to
others.
84. Which of the following notation is used to
denote a regulator unit?
(Noida Metro Maintainer Fitter 2017)
(a) 3 (b) 0.003
(c) 0.3 (d) 3.0
Ans : (c) 0.3 notation is used to denote a regulator unit. 87. In which category does the symbol shown in
85. In which category does the symbol shown in the figure belong to-
the picture belong to-

(VIZAAG Steel Fitter, 2015)

(a) Mandatory Sign (b) Warning Sign
(IOF Fitter, 2016)
(c) Information Sign (d) Prohibition Sign
(a) Mandatory Sign (b) Information Sign
Ans : (b) These are called warning signs. Their shape is
triangular whose background is yellow and the symbol (c) Prohibition Sing (d) Warning Sign
and border are in black. These are used for different Ans : (a) Mandatory Sign- On seeing these type of
types of warnings. These are the following below which signs, we are reminded of security related work, that is,
their use or purpose is also written. they remind us about the safety precautions to be taken
before or after working. For example, wear glasses to
protect eyes, wear shoes to protect the feet etc.

88. In which category does the symbol shown in

the figure belong to-

86. Which category does the symbol shown in the

picture belong to
(IOF Fitter, 2016)
(a) Prohibition Sign (b) Warning Sign
(c) Mandatory Sign (d) Information Sign
Ans : (d) Informational Sign- Safety related
information is given through these types of signs. Their
(CRPF Constable Tradesman, 2016) shape is square. Their background is green and the
(a) Information sign (b) Warning Sign symbol is white the figure gives information about first
(c) Prohibition Sign (d) Mandatory Sign aid.
Ans : (c) Through these types of signs, advice is given
not to do any wrong work due to which accidents in
factories are reduced. The shape of the symbols is
circular due to which the outer roundness of the circle is
in red color and the shape made inside is in black color.
There is a red cross mark on it.
Occupational Safety and Health 192 YCT

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03.
Basic Electricity
■ Electrostatics-Electrostatics is the branch of
physics that deals with stationary electric charges and
the forces between them. It explores concepts like
electric fields, coulomb law, electric potential and
capacitance.
■ Electric Charge:- Electric charge is a physical • In the process the charged object does not transfer
property carried by a matter due to which it can apply electrons to or receive electrons from the object
force on other matter particle. A charged matter can being charged. The charged object merely serves to
apply force and this force is found to be of two types polarize the object being charged.
to explain it we have to discover that charges are of • The object being charged ultimately receives a
two types - charge that is opposite that of the charged object that
(i) Positive Charge is used to polarize it.
(ii) Negative Charge (3) Charging by conduction-
Like charges repel and unlike charges attract each
other.
Basic properties of Electric Charge -
• Additive: Charges can be added by simple rule of
Algebra.
• Quantization of Charge : Electric charges on a body
is not a continuous quantity but it is integral multiple
of charge on one electron. • Charging by conduction involves the contact of a
Q = ± ne charged object to a neutral object. Hence when an
uncharged conductor is brought in contact with a
• Charge is conserved : The total charge of isolated charged conductor, charge is shared between the two
system is always conserved, it may get redistributed. conductors and hence the uncharged conductor gets
Isolated electric charge can neither be created nor charged.
destroyed, it can only be transferred. • During charging by conduction, both objects acquire
238
U = 234 Th + 4 He (Active decay) the same types of charge.
The charges in pair can be created or destroyed. • Electroscope- An electroscope is a device used to
Annihilation:- detect the presence of an electric charge on a body in
the year 1600, British physician William Gilbert
e – + e + 
→γ+ γ (Radiation) invented the first electroscope with a pivoted needle
↓ called versorium.
Gamma rays • Type of electroscope-
There are three types of electroscope
Pair Production:–
(i) Pith-ball electroscope
(ii) Gold- leaf electroscope
(iii) Needle electroscope
• Uses of Electroscope-
The various benefits of an electroscope are
Charging a body – 1. To analyze the electrostatic charges and any ionizing
radiation present in a body.
(1) Charging by rubbing or Frictional-When two
different materials are rubbed, electrons get 2. The nature of the electrical charge is measurable
transferred from one body to another body. using an electroscope.
(2) Charging by Induction - Induction charging is a 3. To compare the magnitudes of two different charges.
method used to charge object another object without ■ Coulomb's law of electrostatics -
charge.
• It is used for charging an object without actually
touching the object to any other charged object.
Basic Electricity 193 YCT
• The law states that if two point charges q1, q2 are Distribution of Continuous Electric Charge ;
separated by a distance r in vacuum the magnitude of • The region in which charges are closely spaced is
the force (F) between them is given by - said to have continuous distribution of charge. It is of
Kq1q 2 three types :-
F=
r2 Linear Charge Surface Charge Volume
1 Density (λ) Density (σ) Charge
Where K = = 9×109 Nm 2 C –2
4πε 0 Density (δ)
(ε0 = Permittivity of free space = 8.85×10–12 C2N–1m–2 ) • It is defined • It is defined as • It is defined
• The law is applicable only for static and point as the charge the charge per as the charge
charges. per unit unit surface per unit
length. area. volume.
• Moving charges may result in magnetic interaction.
• Its unit is • Its unit is • Its unit is
• If charges are extended, Induction may charge the
charge distribution. Coulomb/met Coulomb/mete Coulomb/me
er. r 2. ter3.
• K is arbitrary (we choose any positive value)
dq dq dq
• The choice of K determines the size of the unit of • λ = . • σ= . • δ= .
charge. dL dS dV
• The Separation between the charges must be greater
■ Electric Field :-
than nuclear distance.
• Electric field is space around a charge where its effect
Permittivity and relative permittivity :-
can be experienced, the effect can be strong or weak,
• Permittivity is a characteristics of a medium between we call it intensity of electric field. It is represented
two charges which affect the force between them.
by 'E'.
It is represented by 'ε' (Epsilon).
• Mathematically, Electric field produced by a charge q
Permittivity of free space is represented by 'ε0'. Its
1 q F
dimension is [M–1 L–3T4A2]. at a point 'r' is given by E = 2
ˆr = .
• Relative permittivity is the ratio of absolute 4 πε 0 | r | q 0

permittivity of medium to the permittivity of free • Unit of 'E' = NC–1, Dimension = MLA–1T–3.
space. Electric Field due to a system of Charges :-
ε
εr =
ε0
It is also given by -
Electrostatics Force in free space Electric field in free space
( ε r )m = =
Electrostatics Force in Medium Electric field in medium
It is also equal to dielectric constant k.
(i) (εr) Free space = 1.
(ii) Any medium has permittivity > 1. • If we place a unit test charge q0 near n point charges
(iii) For water 'k' = 81 q1, q2, .......... qn then the net force F from the n point
(v) For metal k = ∞. charges acting on the test charge is
Force between Multiple charges : Superposition F = F1 + F2 + F3 + .......... + Fn .
principle -
• According to the principle of Superposition total
Then net electric field at the position on the test
force on a given charge due to number of charge is
charge is-
the vector sum of individual forces acting on that
E = E1 + E2 + E3 + ......... En
charge due to the presence of other charges.
Let the charges be q1, q2, q3, ........ qn exert force F12, F1 F2 F3 F
= + + + ......... + n
F13, ........ F1n on charge q1. The total force on charge q0 q0 q0 q0
q1 is given by
1 q1 1 q2 1 q3
1  q1q 2 qq qq  E= rˆlP + rˆ2P + rˆ3P + ........
F1 = F12 + F13 + .........F1n =  rˆ12 + 1 2 2 rˆ13 + ........ 1 2 2 rˆ1n  4πε 0 r1P2 4πε 0 r2P2 4πε 0 r3P2
4πε 0  r122 r13 r1n 
n
1 qi
∑r
n
q qi ˆriP
= 1
4πε0
∑ rˆ
2 1i
i = 2 r1i
E(r) =
4πε 0 i=1
2
iP

Basic Electricity 194 YCT

Physical Significance of Electric field - • Lightning-During thunderstorm as the static charge
• Electric field is a characteristics of the system of build up in storm cloud increases, the electric field
charges. It is independent of the test charge that you surrounding the cloud becomes stronger too.
place at a point to find the field. Normally, the air surrounding a cloud would be a good
• Since force is a vector quantity so electric field is a insulator to prevent the discharge of electrons to the
also vector quantity. earth yet the strong electric field surrounding a cloud
• Electric field can be detected only by its effects are capable of ionizing the surrounding air and making
(forces) on charges. It has an independent dynamics it more conductive. The ionization involves the
of a force on q2. Effect of any motion of q1 and shredding of electrons from the outer shells of gases
charge q2 cannot arise instantaneously. molecules. These molecules that compose air are thus
The accelerated motion of charge q1 produces turned into a soup of positive ions and free electrons.
electromagnetic waves, which then propagate with The insulating air is transformed in to conductive
the speed of light c reach q2 and causes a force on q2. plasma. The ability of a storm cloud's electric fields to
Electric field lines :- transform air into a conductor makes charge transfer
(in the form of a lightning bolt) from the cloud to the
• Electric field lines are imaginary smooth curves
drawn in sphere to represent electric field over there. ground or even to other clouds.
Characteristic of electric field lines:-
• Start from positive charge terminate at negative
charge. These are discontinuous curve.
• Field lines are always smooth curves. Tangent at any
point gives direction of electric field at that point.
• Two lines never cross each other because if they
cross that will indicate two directions at that point
which is not possible.
• Crowding of Electric field lines indicate relative
strength of electric field.
• Electric field lines are always at right angle to the
Surface.
• Number of lines assumed to be linked with a unit
1 1 Electric flux -
charge are = .
ε 0 8.85 ×10–12 • Electric flux linked to surface area is a quantity
• Lines behave like stretched string trying to decrease (Scalar) formed by intensity of field E and area normal to
their strength. this explains force of attraction it A, such that flux linked to surface area is–
between positive and negative charges. • A is the surface area perpendicular to, φE = E ⋅ A
• Flux = Intensity of electric field × Area linked
+ – φE = E A cos θ

• The lines laterally repel each other (normal to line)

that indicate the force of repulsion between similar
charges.
Electric field lines due to different distribution If E is not uniform throughout the area 'A' then φ =
∫ E i dA
• It is scalar Quantity and SI unit is N-m2C–1.
• 'φ' does not depend on the -
• φE represents the number of field lines through
surfaces.
• Flux is zero for a surface parallel to the field
(Normal is at 900 to E)
(i) Shape and size of the closed surface.
+q −q (ii) The charges located outside the closed surface.
■ Electric Dipoles –

Basic Electricity 195 YCT

• Pair of two equal and opposite point charges attached Equipotential Surface –
at a fixed distance is called electric dipole. • Every point on a surface is at same potential called
• Na+ Cl– molecule represents an electric dipole. equipotential surface.
• Dipole Moment ( P ) = q×2l (i) Electric lines always join the equipotential surface
Where P is vector quantity its direction is along the perpendicularly.
line from negative to positive charge. (ii) Work done in moving a charge from one point to
• SI unit - Coulomb meter (Cm) other on an equipotential surface is zero.
• Dimension - [LTA] (iii) It is not affected by the path.
Dipole kept in Electric field - Weq
(iv) = VA – VB ⇒ W = 0
q
(v) Equipotentials are parallel to each other (means
does not intersect each other).
(vi) Equipotential potential surface are planer in an
uniform electric field.
(vii) In a family of equipotential surface the surfaces are
• Torque(τ) = P × E = PE sin θ
closer together where the electric field is stronger
Where θ is angle between P and E and farther apart where field weaker.
If P is along E (viii) Equipotential surface due to line charge is
θ = 0º, τ=0 (Stable equilibrium ) cylindrical.
(ix) Equipotential surface due to an isolated point
If P is opposite to E
charge is spherical.
θ = 180º , τ = 0 (Unstable Equilibrium)
■ Electric potential energy -
Work done in Rotating a dipole – The electric potential energy of a system of fixed
θ2
W = ∫ dW = ∫ τdθ = ∫ PE sin θdθ = PE [cosθ1– cosθ2] point charges is equal to the work that must be done
θ1
by an external agent to assemble the system, bringing
■ Electric Potential - each charge from infinity.
• The electric potential at a point in an electric field is
• Potential Energy of two Charge System -
the ratio of work done in carrying a test-charge from
infinity to that point to the magnitude of the test Potential energy of two point charges system, that
charge. It is given by – contains charges q1 and q2 separated by a distance 'r'
W 1 q1q 2
V= is given by U=
q 4πε 0 r
• Its S.I. unit is J/c or volt and dimension [ML T A ]. • Potential energy in a dipole –
2 –3 –1

Kq
• For point charge, V = .
r 2a
• Electric potential due to an electric dipoles
P
At axis of dipole V = K 2 .
r
On a Equatorial line V = 0
At any point a line making angle θ Potential energy of dipole is given by-
P cos θ KP.r U = – P.E cos θ
V= K = 3
r 2
r If dipole is kept along E then U is given by -
n
q U = – P.E
• For Several point charges, V = K ∑ i Where, P = dipole moment
i=1 ri
E = Electric field
Potential gradient :-
• The rate of change of potential with distance is ■ Motion of Charged Particle in electric field
electric field is called Potential gradient. • Consider a charge particle having charge 'q' and mass
dV m is initially at rest in an electric field of strength E.
• Potential gradient = , its unit is V/m. The particle will experience an electric force which
dr
causes its motion.
• Relation between potential gradient and electric field
The force experienced by the charge particle is F,
 dV  where
intensity is given by E = –   .
 dr  F = qE
Basic Electricity 196 YCT
 Acceleration produced by this force is Flux linked through surface element ∆s is
F qE q
a= = ............... (i) ∆φ = E. ∆S = ∆S
m m 4πε 0 r 2
Total flux linked through the entire surface S
q q
φ= ∫ ∆φ = ∫ E.∆S =
4πε 0 r 2 ∫ ∆S =
4πε 0 r 2
S

For sphere S = 4πr2

At point P particle is at rest and after some time 't' , it
q q q
reaches the point Q and attains velocity v which is φ = .4πr 2 = ⇒φ =
given by, v = at 4 πε 0 r 2
ε 0 ε 0

If potential difference between P and Q be ∆V and Where, q = net charge enclosed by given surface.
the distance between them is d, then Similarly for a cube
qEt 2q∆V
v= = q
m m Total electric flux linked with whole cube =
ε0
• Momentum of charge particle-
As momentum, q
and electric flux linked with one face of cube =
6ε 0
 qEt 
P = mv= m   ⇒ P = qEt
 m  • This law is especially useful in determining electric
2q∆V field when source distribution has simple symmetry.
= m = 2mq∆V
m • This law is true for closed surface only.
• Kinetic Energy of Charged Particle - • Charges outside makes the flux but net flux is only
Kinetic Energy gained by the particle in time t is- due to charge enclosed.
2
1 1  qEt  q2E2 t 2 • Use the gauss theorem with symmetrical surface to
(a) K.E. = mv 2 = m   =
2 2  m  2m calculate E at a point.
1 2q∆V
(b) K.E. = m × = q ∆V • Gauss theorem depends on inverse square law.
2 m
Note:- "Gauss's Law depends upon Symmetry, so that
■ Gauss's Law -
if we can not show symmetry exist then we can not
• According to Gauss theorem the electric flux linked
us Gauss law"
1
with a closed surface is times the charge For example Electric field due to line charge
ε0
enclosed by the surface. distribution.
Gaussian Surface (Imaginary Surface)-
• The surface that we choose for the application of
Gauss's law is called Gaussian surface.
• Gaussian surface does not applicable for discrete
charge because electric field due to a system of
discrete charges is not well defined at the location of
any charge.
• Gaussian surface can pass through a continuous
charge distribution.
• It is an imaginary surface; homogenous in nature,
symmetrical surface.

Basic Electricity 197 YCT

 Applications of Gauss' Theorem
• Electric field intensity due to an infinite line charge -
1 λ
Electric field, E = ×
2πε 0 r
λ r 
Also, Potential difference = ln  2 
2πε 0  r1 
Where λ is linear density and r is distance from
the line charge.
Electric potential for infinite line charge is not
defined.
• Electric field near an infinite plane sheet of charge -
σ
Electric field, E =
2ε 0
Where, σ = surface change density.

• Electric field for a long charged conducting cylinder-

For r≥R
q
Electric field, E=
2πε 0 r
for, r < R, E = 0

• Electric field just outside charge conductor-

σ
E= , ( E inside = 0 )
ε0
• Electric field due to two infinite parallel sheets of Charge-
σ
E= { for both sheets having same charge density}
ε0
• For non-conducting long sheet of surface charge density 'σ'-
σ
E=
2ε 0
• For conducting long sheet of surface charge density 'σ' -
σ
E=
ε0
• For uniformly Charged Spheres –
Figure Electric field (E) and electric Graphs
potential (V)
For r≥R
1 q 1 q
E= 2
, V=
4πε 0 r 4πε 0 r
for , r < R
Charged conducting solid sphere
1 q σR
E=0,V= =
4πε 0 R ε0

Basic Electricity 198 YCT

 For r≥R
1 q 1 q
E= 2
, V=
4πε 0 r 4πε 0 r
for, r < R
Charged Non conducting solid sphere
1 qr
E=
4πε 0 R 3

1 q ( 3R – r )
2 2

V=
4πε 0 2R 3

1 xq
Ex =
( )
3
4πε 0 x 2 + a 2 2

1  2q 
Emax =  
4πε 0  3 3a 2 
Charged Ring On the axis of uniformly charged
ring
1 q
4πε 0 ( x 2 +a 2 )1/2
At centre x = 0
1 q
V=
4πε 0 a
for r ≥ R
1 q 1 q
E=  2 ,V =  
4πε 0  r  4πε 0  r 
For r < R
1 q
E = 0, V =  
4πε 0  R 
For conducting/ non-conducting
spherical shell

----
■ Electrostatic Shielding - • At the surface of charged conductor electrostatic field
must be normal the surface at every point.
• The interior of a conductor can have no excess charge
in the static situation.
• Electrostatic potential is constant throughout the
volume of the conductor and has the same value on
its surface.
• Electric field at the surface of charged conductor is
σ
.
ε0
• Any cavity in conductor remains shielded from ■ Millikan’s Oil Drop Experiment :-
outside electric influence (i.e. field inside the cavity is • Millikan allowed charged tiny oil droplets to pass
always zero). This is known as Electrostatic through a hole an electric field. By varying the
Shielding. strength of the electric field the charge over an oil
■ Electrostatic of Conductor :- droplet was calculated, which always came as an
• Inside a conductor, electrostatic field is zero. integral value of 'e'.
Basic Electricity 199 YCT
 • The capacitance depends only on the geometry of the
conductors and not on an external source of charge or
potential difference.
Energy store in a charged capacitor - Energy
stored in a charged capacitor is defined as the total
amount of work in charging the capacitor stored up in
the capacitor in the form of electrical potential
Calculation: energy.
Fup = Fdown
Fup = Q.E 1 1 Q2 1 2
V = CV2 = = Q
Fdown = m.g 2 2 C 2
Q is an electron's charge, E is the electric field, m is
the droplet's Q.E = m.g
m.g Factors affecting capacitance-
Q= The value of capacitance depends upon the physical
E
Conclusion: features, area of the capacitor plates 'A' distance
The charge over any oil droplet is always an integral between the plates 'd' and the permittivity of the
value of e (1.6 × 10–19). Hence, the conclusion of A
dielectric medium 'E' C = E ×
Millikan's oil Drop Experiment is that the charge is α
said to be quantized, i.e. the charge on any particle
• Surface area - Higher the value of the surface area,
will always e or an integral multiple of e.
the higher the capacitance.
Capacitance and Capacitors • The distance, d between the two plates. The smaller
■ Capacitor :- A capacitor is a device that stores the distance, the greater is the capacitance.
electrical energy. It consists of a pair of conductors of
any shape and size carrying charges of equal • Dielectric material - The type of material separates
magnitudes and opposite signs and separated by an the two plates called the "di-electric" the higher the
insulating medium. permittivity of the dielectric, the greater is the
capacitance.
Uses of a capacitor-
The capacitors have both electrical and electronic
applications. They are used or several things such as
filters, energy storage systems, engine starters, signal
processing devices, etc.
• Capacitors are used for storing energy, which can be
used by the device for temporary power outages
whenever they need additional power.
• Capacitors are used for blocking DC current after
getting fully charged and yet allow the AC current to
pass through the circuit of a circuit.
Capacitance of a Capacitor -
• Capacitors are used as sensor for several things like
• The ability to store charge by a capacitor is called
capacitance of the capacitor. measuring humidity, fuel levels, mechanical strain etc.
• It is also defined as the amount of charge required to • Capacitors can be used in a time dependent circuit.
raise the potential of the capacitor by one unit (In SI This could be connected to any LED or loudspeaker
one volt). system, and it's likely that only flashing light/regular
If 'Q' is the amount of charge given and 'V' is beeping uses a timing capacitor.
potential of capacitor, then capacitance of the Dielectric and Polarization :-
capacitor is given by
Q
• A dielectric is an insulating material in which all
C= . electrons are tightly bonded to the nuclei of the
V
atoms. Hence free movement of charges in not
• SI unit of capacitance is Farad or F.
possible. It is given by
1 Farad = 1 Coulomb /Volt.
• Dimension of capacitance = [M L T A ].
–1 –2 4 2 C ε
k= = = εr
• Capacitance is a scalar Quantity. C0 ε 0

Basic Electricity 200 YCT

where, Parallel Plate capacitor :-
C = capacitance when space between pair of conductor • Most commonly used capacitor is parallel plate
is filled with dielectric.
capacitor, which consists of two charged parallel
C0 = capacitance when space is vacuum.
plates separated by a small distance. Capacitance of a
ε0 = permittivity of free space, parallel plate capacitor with vacuum between the
ε = permittivity of medium. plates is given by
εr = relative permittivity
• For a polar and non-polar molecule the dipole moment
per unit volume is called polarization. It is given by
P = χe E
Where, χe is a constant characteristics of the dielectric
and and is known electric susceptibility of the dielectric
medium.
Spherical Capacitor:- εA
Without dielectric– C = 0 Farad
• A spherical capacitor consists of a solid or hollow d
spherical conductor of radius a, surrounded by If the space between capacitor filled with dielectric
another hollow concentric spherical of radius b
then–
ε 0 kA
C= Farad
d
where,
k = dielectric constant of the medium between the plates
• Its capacitance C is given by - A = Area of plates
4πε 0 ba d = distance between the plates
C= Farad.
b–a If medium is partly filled with air then-
• If radius of outer conductor approaches to infinity
then,
C = 4πε0a Farad.
• When inner sphere is earthed then, it serves as two ε0A
capacitors in parallel where, C=
 t
C1 = 4πε0b Farad. (Outer surface and earth) d–t – 
4πε 0 ba  k
C2 = Farad. (Region between two spheres)
b–a
Capacitance of an Isolated Spherical Capacitor
When a dielectric slab of thickness 't' and relative
permittivity εr is introduced between the plates of an air
capacitor, then the distance between the plates is
 t 
effectively reduced by  t −  irrespective of the
 ε r 

position of the dielectric slab.

If the space between plates is completely filled with
multiple dielectrics-

• C = 4πε0kR in a Medium ε 0A
C=
t1 t 2 t 3
C = 4πε0R in a Air + +
k1 k 2 k 3
Where, ε0 = permittivity in free space
R = Radius of sphere.
k = dielectric constant

Basic Electricity 201 YCT

Cylindrical Capacitor :- 1ε A V 2
 ε0A 
• It consists of two co-axial cylinders of radii a and b =  0  C = 
2  d  Ad  d 
the outer conductor is earthed. The dielectric constant 2
of the medium filled in the space between the 1 V
= ε0  
cylinders is k. 2 d
The capacitance per 1 V 
unit length is C = = ε0E2  = E
2 d 
2πε 0 k
• Energy density is the property of electric field and
b above formula is valid in all cases. The unit of energy
ln  
a density is J/m3.
■ Effect of Dielectric on Charge, Potential
Difference, Field and Energy of Capacitor-
■ Combination of Capacitors - Effect of dielectric on various parameters of
• Capacitors in series:- In this arrangement all the capacitors can be seen in two ways-
capacitors when uncharged get the same charge Q but • If Charge is held constant, i.e. Battery is
the potential difference across each will differ (If the disconnected after charging -
capacitance are unequal).
C 0 ,V,
0
E0 ,U 0
1 1 1 1 1
= + + + .......
Ceq C1 C2 C3 Cn
C,V, E ,U

(i) Charge remains constant, q = q0.

• Capacitors in Parallel :- When one plate of each
(ii) Capacity increases as C = kC0.
capacitor is connected to the positive terminal of the
battery & the other plate of each capacitor is (iii)Potential difference between the plates decreases as
connected to the negative terminals of the battery, then q q V
V= = 0 = 0 .
the capacitors are said to be in parallel connection. The C kC0 K
capacitor have the same potential difference , 'V' but
(iv) Electric field between the plates decrease as
the charge on each one is different (If capacitance are
unequal). E
E= 0
k
(v)The energy stored decreases as
Ceq = C1 + C2 + C3 q2 q 20 U0
+ ......... + Cn. U= = = .
2C 2kC0 k
■ Energy stored in a charged capacitor:- • If Potential is held constant, i.e. battery remains
• Energy stored in a charged capacitor is defined as the attached
total amount of work in charging the capacitor stored
up in the capacitor in the form of electrical potential
energy.
1 1 Q2 1 C0,V,
0 E0,U0 C,V, E,U
U = CV 2 = = QV
2 2 C 2
• This energy is stored in the electrostatic field setup in
the dielectric medium between the conducting plates (i) Potential difference remains constant i.e. V = V0 as
of the capacitor. battery is a source of constant potential difference.
Energy Density :- (ii) Capacity increases as C = kC0.
• The energy stored in a capacitor is not localized on (iii) Charge on capacitor increases as q = CV = (kC0)V
the charges or the plates but is distributed in the field. = kq0 .
In case of a parallel plate capacitor, electric field is (iv) Electric field remains unchanged as
only between the plates in a volume (A×d) which is V V
so called energy density. It is given by- E =   = 0 = E0 .
d d
1 2
CV (v) Energy stored in the capacitor increases as -
Energy 2
Energy density = = 1 1 1
Volume A×d U = CV 2 = kC0 V02 = kU 0
2 2 2

Basic Electricity 202 YCT