PHYSICS LABORATORY- MANUAL

(As per 2023 Academic Regulation- Revised)

I – SEMESTER B.E. & B. Tech.

(Common to All Branches)

DEPARTMENT OF PHYSICS

V.S.B. ENGINEERING COLLEGE, KARUR

N.H. 67, COVAI ROAD, KARUDAYAMPALAYAM, KARUR-639 111

Phone: 04324-286408, 286212

E-mail: physics@vsbec.com

Website: www.vsbec.edu.in
 23BSP102 Physics and Chemistry Laboratory L T P C
0 0 4 2
(Common to all branches except CSBS)
Any Seven Experiments
OBJECTIVES:
 To learn the proper use of various kinds of physics laboratory equipment.
 To learn how data can be collected, presented and interpreted in a clear and concise
manner.
 To learn problem solving skills related to physics principles and interpretation of
experimentaldata.
 To determine error in experimental measurements and techniques used to minimize
such error.
 To make the student as an active participant in each part of all lab exercises.

1.Torsional pendulum - Determination of rigidity modulus of wire and moment of

inertia ofregular and irregular objects.
2. Simple harmonic oscillations of cantilever.
3. Non-uniform bending - Determination of Young’s modulus.
4. Uniform bending – Determination of Young’s modulus.
5. Laser- Determination of the wavelength of the laser using grating.
6. Air wedge - Determination of thickness of a thin sheet/wire.
7. a) Optical fibre -Determination of Numerical Aperture and acceptance angle.
b) Compact disc- Determination of width of the groove using laser.
8. Ultrasonic interferometer – determination of the velocity of sound and
compressibility ofliquids.
9. Post office box -Determination of Band gap of a semiconductor.
10. Michelson Interferometer.
11. Melde’s string experiment.
TOTAL PERIODS: 30
OUTCOMES:
Upon completion of the course, the students should be able to
 Understand the functioning of various physics laboratory equipment.
 Use graphical models to analyze laboratory data.
 Use mathematical models as a medium for quantitative reasoning and describing physical
reality.
 Access, process and analyze scientific information.
 Solve problems individually and collaboratively.

COs PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11 PO12 PSO1 PSO2 PSO3

CO1 3 2 3 1 1 - - - - - - - - - -
CO2 3 3 2 1 1 - - - - - - - - - -
CO3 3 2 3 1 1 - - - - - - - - - -
CO4 3 3 2 1 1 - - - - - - - - - -
CO5 3 2 3 1 1 - - - - - - - - -
AVG. 3 2.4 2.6 1 1 - - - - - - - - - -
23BSP103 Engineering Physics Laboratory L T P C
0 0 4 2
(For I year CSBS students only)
Any Eight Experiments
OBJECTIVES:
 To learn the proper use of various kinds of physics laboratory equipment.
 To learn how data can be collected, presented and interpreted in a clear and concise
manner.
 To learn problem solving skills related to physics principles and interpretation of
experimentaldata.
 To determine error in experimental measurements and techniques used to minimize
such error.
 To make the student as an active participant in each part of all lab exercises.

1.
Torsional pendulum - Determination of rigidity modulus of wire and moment of
inertia ofregular and irregular objects.
2. Simple harmonic oscillations of cantilever.
3. Non-uniform bending - Determination of Young’s modulus.
4. Uniform bending – Determination of Young’s modulus.
5. Laser- Determination of the wavelength of the laser using grating.
6. Air wedge - Determination of thickness of a thin sheet/wire.
7. a) Optical fibre -Determination of Numerical Aperture and acceptance angle.
b) Compact disc- Determination of width of the groove using laser.
8. Ultrasonic interferometer – determination of the velocity of sound and
compressibility ofliquids.
9. Post office box -Determination of Band gap of a semiconductor.
10. Michelson Interferometer.
11. Melde’s string experiment.
TOTAL PERIODS: 60
OUTCOMES:
Upon completion of the course, the students should be able to
 Understand the functioning of various physics laboratory equipment.
 Use graphical models to analyze laboratory data.
 Use mathematical models as a medium for quantitative reasoning and describing physical
reality.
 Access, process and analyze scientific information.
 Solve problems individually and collaboratively.

COs PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11 PO12 PSO1 PSO2 PSO3

CO1 3 2 3 1 1 - - - - - - - - - -
CO2 3 3 2 1 1 - - - - - - - - - -
CO3 3 2 3 1 1 - - - - - - - - - -
CO4 3 3 2 1 1 - - - - - - - - - -
CO5 3 2 3 1 1 - - - - - - - - -
AVG. 3 2.4 2.6 1 1 - - - - - - - - - -
Program Outcomes (PO)
PO1: Engineering knowledge
Apply the knowledge of mathematics, science, engineering fundamentals, and an
engineering specialization to the solution of complex engineering problems.
PO2: Problem analysis
Identify, formulate, research literature, and analyse complex engineering problems
reaching substantiated conclusions using first principles of mathematics, natural sciences,
and engineering sciences.
PO3: Design/development of solutions
Design solutions for complex engineering problems and design system components
or processes that meet the specified needs with appropriate consideration for the public
health and safety, and the cultural, societal, and environmental considerations.
PO4: Conduct investigations of complex problems
Use research-based knowledge and research methods including design of
experiments, analysis and interpretation of data, and synthesis of the information to
provide valid conclusions.
PO5: Modern tool usage
Create, select, and apply appropriate techniques, resources, and modern
engineering and IT tools including prediction and modeling to complex engineering
activities with an understanding of the limitations.
PO6: The engineer and society
Apply reasoning informed by the contextual knowledge to assess societal, health,
safety, legal and cultural issues and the consequent responsibilities relevant to the
professional engineering practice.
PO7: Environment and sustainability
Understand the impact of the professional engineering solutions in societal and
environmental contexts, and demonstrate the knowledge of, and need for sustainable
development.
PO8: Ethics
Apply ethical principles and commit to professional ethics and responsibilities and
norms of the engineering practice.
PO9: Individual and team work
Function effectively as an individual, and as a member or leader in diverse teams,
and in multidisciplinary settings.
PO10: Communication
Communicate effectively on complex engineering activities with the engineering
community and with society at large, such as, being able to comprehend and write
effective reports and design documentation, make effective presentations, and give and
receive clear instructions.
PO11: Project management and finance
Demonstrate knowledge and understanding of the engineering and management
principles and apply these to one’s own work, as a member and leader in a team, to
manage projects and in multidisciplinary environments.
PO12: Life-long learning
Recognize the need for, and have the preparation and ability to engage in
independent and life-long learning in the broadest context of technological change.
 CONTENTS

I. LAB INSTRUCTIONS

II. MEASURING INSTRUMENTS

1. Screw Gauge

2. Vernier Caliper

3. Travelling Microscope

4. Spectrometer

III. LIST OF EXPERIMENTS

Knowledge Name of the Experiments COs POs PSOs
level
K5 Determination of rigidity modulus - Torsion pendulum. 1 1,2,3,4,5 -
K5 Simple Harmonic oscillations of cantilever. 5 1,2,3,4,5 -
K5 Determination of Young’s modulus by non- 2 1,2,3,4,5 -
uniform bending method.
K5 Determination of Young’s modulus by uniform bending 2 1,2,3,4,5 -
method
K5 Determination of wavelength, and particle size using 2 1,2,3,4,5 -
Laser.
K5 a) Determination of Numerical aperture and 3 1,2,3,4,5 -
acceptance angle in an optical fiber.
(b) Compact disc- Determination of width of
groove using laser.
K3 Ultrasonic interferometer - Determination of velocity of 3 1,2,3,4,5 -
sound and compressibility of liquids.
K5 Melde’s string experiment. 4 1,2,3,4,5 -
 1. GENERAL LAB INSTRUCTIONS

1. The students should attend the lab neatly with proper prescribed uniform.

2. The record notebook should be covered with the laminated brown sheet
neatly and they should bring it to every lab class.

3. Before any cycle of experiments, a class is spent on demonstrating those

experiments. The students should not miss that class for any reason and they
have to be very attentive in that class.

4. They should read the procedure thoroughly for the lab experiment from the
manual and come well prepared.

5. They should bring the required things like scientific calculator, eraser,
pencil, pen etc., to every lab class. Borrowing things is not allowed.

6. They should not go to others table leaving their place without taking
permission from the staff. They should maintain silence in the class.

7. They should do the experiment systematically and write their observations

neatly in the record note book with pen. After writing a few readings in the
beginning, they should show the record note book to their faculty member
and get attestation for the readings from the faculty. After completing the
experiment, they should do the calculations neatly.

8. They should complete the calculation in the lab class itself and get the
signature from the staff. In case if they are not able to complete, they should
get attestation from the staff in the record note book for the readings taken
 and get the result corrected the next day itself, by submitting the notebook in
the lab. They have to collect their note book from the staff after a day.
9. They should not miss any lab class. This will be viewed very seriously. If
they miss the lab class due to unavoidable reason, they will be allowed for
the next lab provided they submit a letter signed by the parent or Deputy
warden (hosteller) stating the reason. It is the responsibility of the students to
complete the missed experiments as soon as possible after getting permission
from the faculty in-charge.
10. In every lab class, the students have to sign in a register while receiving the
apparatus from the lab assistants. After completing the experiment, they
should hand over the apparatus and sign in the register again, failing which it
would be assumed that they haven't returned the apparatus and the cost of the
apparatus will be collected from them. So it is the responsibility of the
students to return the apparatus to the lab assistants as soon as they complete
the lab work.

INSTRUCTIONS FOR WRITING IN RECORD NOTE

Before coming to the lab, the students should write the experiment number,

date, aim, formula, least count calculation, ray diagram or circuit diagram,

tabular column neatly in the record note book. The record note book will be

checked in the beginning of the lab class.

 RECORD NOTE LAYOUT

1. Title of the Experiment :

2. (Right hand side)

3. Date of Commencement : (Right hand side)

4. Date of Completion and reporting : (Right hand side)

5. Objectives of the experiment : (Right hand side)

6. Aim of the experiment : (Right hand side)

7. Apparatus required : (Right hand side)

8. Formula in detail : (Right hand side)

9. Procedure of the experiment : (Right hand side)

10. Experimental setup/Circuit diagram : (Left hand side)

11. Tabular column : (Left hand side)

12. Calculation : (Left hand side)

13. Result : (Right hand side)

14. Learning outcome achieved : (Right hand side)

 MEASURING INSTRUMENTS

1. SCREW GAUGE

1. Aim:
To determine the thickness of a beam.

2. Apparatus required:

Screw gauge and meter scale

3. Description:

It is based upon the principle of a screw. It consists of a U-shaped metal frame.

One end of which carries a fixed stud ‘A’ whereas the other end ‘B’ is attached to a
cylindrical tube as shown in Fig. 1. A scale graduated in millimeters is marked on the
cylindrical tube along its length. It is called Pitch scale.

Fig. 1 Screw Gauge

The screw carries a head H which has a beveled edge. The edge is divided into 100
equal divisions. It is called the Head scale H.S. When the head is rotated, the head scale
moves on the pitch scale.

4. Procedure

a. To find the least count (LC) of the screw gauge

Least count of a screw gauge is the distance through which the screw tip moves
when the screw is rotated through one division on the head scale.

Distance moved by the head scale on the pitch scale

Pitch =
Number of rotations given to the head scale
 Pitch
Least Count (LC) =

Total number of divisions on the head scale

To find the pitch, the head or the screw is given say 5 rotations and the distance
moved by the head scale on the pitch scale is noted. Then by using the above formula,
the least count of the screw gauge is calculated.
5 mm
Pitch =
5 = 1 mm
1 𝑚𝑚
Least Count = = 0.01 mm
100

The screw head is rotated until the two plane faces A and B are just in contact.

b. To find the zero correction (ZC)

i) Nil error
If the zero of the head scale coincides with the zero of the pitch scale and also lies on
the base line (B.L) the instrument has no zero error and hence there is no zero correction
(See Fig. 2).

Fig. 2 Zero error

ii) Positive zero error
If the zero of the head scale lies below the base line (B.L) of the pitch scale then
the zero error is positive and zero correction is negative. The division on the head scale,
which coincides with the base line of pitch scale, is noted. The division multiplied by the
least count gives the value of the positive zero error. This error is to be subtracted from
the observed reading i.e. the zero correction is negative (See Fig. 3).
 Fig. 3 Positive Zero Error

Example

If 5th division of the head scale coincides with the base line of the pitch scale then

Zero error = +5 divisions

Zero correction = - (Z.E x LC) = - (5 x 0.01) = - 0.05 mm.

iii) Negative zero error

If the zero of head scale lies above the base line (B.L) of the pitch scale, then the
zero error is negative and zero correction is positive. The division on the head scale
which coincides on the base line of pitch scale is noted. This value is subtracted from the
total head scale divisions. This division multiplied by the least count gives the value of
the negative error. This error is to be added to the observed reading i.e. zero correction is
positive (See Fig. 4).

Fig. 4 Negative Zero Error

Example

If the 95th division of the head scale coincides with the base line of the pitch scale
then,
Zero error = -5 divisions
Zero correction = + 0.05 mm
5. To find the thickness of the glass plate
The glass plate is gently gripped between the faces A and B. The pitch scale
reading and the head scale coincidence are noted. The readings are tabulated.
 Fig. 5 Screw Gauge Readings

Pitch Scale Reading (PSR)

Number of pitch scale division just in front of the head scale fully completed is
noted (see Fig. 5). It is measured in millimeter.

Head Scale Coincidence (HSC)

Coincidence of head scale division on the base line of the pitch scale is also noted.

Screw gauge Reading: See Fig. 3

L.C = 0.01mm

Zero Error = ± 5 div. Zero Correction (ZC) = 0.05 mm

Pitch scale Head scale Head Scale Total Reading Correct Reading
Reading Coincidence Reading= (TR)= = TR ZC
PSR+HSR
(PSR) (HSC) HSCLC
S. No

10-3 m div 10-3 m 10-3 m 10-3 m

Mean thickness of the beam = _ mm

Thickness of the glass beam = __ x 10-3metre.

 2. VERNIER CALIPER

1. Aim:

To measure the external diameter, internal diameter and length of the given
object.

2. Apparatus:

Vernier Calipers and Wooden block

3. Description:

The vernier calipers consist of a long rigid rectangular steel strip called the main
scale (M.S) with a jaw (A) fixed at one end at right angles to its length as shown in Fig.1.
The main scale is graduated both in centimeters and inches. The second jaw (B) carrying
a vernier scale and capable of moving along the main scale can be fixed to any position
by means of a screw cap S. The vernier scale is divided into 10 divisions, which is
equivalent to 9 main scale divisions (M.S.D). So the value of 1 vernier scale division is
equal to 9/10 M.S.D. The value of 1 M.S.D. is 1 mm

Fig.1 Vernier Calipers.

Procedure:

a. To find the Least Count (LC) of the vernier calipers: (see Fig. 2)

It is the smallest length that can be measured accurately by the vernier calipers
and is measured as the difference between one main scale division and one vernier scale
division.
 Fig. 2 Vernier scale and main scale .

Least Count (LC) = 1 M.S.D — 1 V.S.D

Value of 1 M.S.D = 1 mm

No of divisions on the vernier scale = 10 divisions.

10 V.S.D = 9 M.S.D

1 V.S.D = 9/10 M.S.D = 9/10 x 1 mm = 9/10 mm

L.C.= 1 M.S.D - 1 V.S.D =1 mm - 9/10 mm

=0.1 mm = 0.01 cm L.C. = 0.01 cm

b. To find the Zero Correction (ZC):

Before taking the readings with the vernier calipers, we must note the zero
error of the vernier calipers. When the two jaws of the vernier calipers are pressed
together, if the zero of the vernier scale coincides with the zero of the main scale the
instrument has no error, otherwise there is a zero error. The zero error is positive if
the vernier zero is after the main scale zero. The zero error is negative when the
vernier zero is before the main scale zero. Ordinarily, the zero error is negligible in
the case of vernier calipers and so zero error can be considered to be nil.

c. To find the length of the given object:

The given object is firmly gripped between the jaws, taking care not to press it
too hard. The main scale reading and the vernier coincidence are noted. The main
scale reading is the reading on the main scale that is just before the vernier zero. The
 vernier scale coincidence is found by noting the vernier division that coincides with
any one of the main scale. Then the vernier scale reading is found by multiplying the
vernier coincidence with the least count. The observations are repeated for various
positions of the object.

Fig. 3 Vernier Caliper readings

Example:

Vernier Calipers readings: (See Fig. 3)

LC = 0.01cm

Main scale Vernier Vernier Scale Total Reading Correct Reading

Reading scale Reading= (TR)= = TR ZC
Coincidence MSR+VSR
(MSR) VSCLC
S. No
(VSC)

10-2 m div 10-2 m 10-2 m 10-2 m

1.

2.

3.

4.

5.
 3. TRAVELLING MICROSCOPE
1. Aim:

To learn the parts of a Travelling microscope and to find the distance between two
horizontal lines.

2. Apparatus:

Reading lens and capillary tube

3. Description:

It is a compound microscope attached to a graduated vertical pillar, which is

mounted on rigid platform (Fig. 1). The platform is provided with three leveling screws.
The microscope can be set with its axis either in the vertical or the horizontal position.
The microscope can be moved in the vertical or horizontal direction by means of a screw
arrangement attached to it. The distance through which the microscope is moved is read
on the scale. There are two scales one for horizontal movement and the other for the
vertical movement. Each scale has a main scale (M1, M2) and a vernier scale (V1, V2).
The vernier moves with the microscope. As in the spectrometer, there is a set of main
screw and fine adjustment screw, for the horizontal and the vertical movements. One set
is fixed to the pillar for vertical movement and the other set is fixed to the platform for
horizontal movement. The eyepiece of the microscope is provided with cross-wires. The
image of an object is focused by the microscope using a side screw (focusing screw)
attached to the microscope.

4. Procedure:

a. To find the Least Count (LC) of the travelling microscope:

The main scale is graduated in mm. There are 50 V.S.D equivalents to 49 M.S.D. The
value of one M.S.D. is 0.5 mm = 0.05 cm

LC = 1 M.S.D –1 V.S.D.

1 M.S.D = 0.05 cm

50 V.S.D = 49 M.S.D
 1 V.S.D = 49/50 x 0.05 = 0.049 cm
LC = 0.05 -- 0.049 cm

LC = 0.001cm

Fig. 1 Travelling Microscope

b. To read a reading:

When the microscope is clamped by the main screw or fine adjustment screw at
any position, the reading is taken in the vertical scale or in the horizontal scale according
to the requirement. M.S.R and V.S.R are taken as in the vernier calipers. For example
see Fig. 2, and write the M.S.R and V.S.R.

Fig. 2 Vernier and Main scale

Note:

In the Vernier calipers, travelling microscope and the spectrometer, the MS zero
may coincide with the VS zero. In such cases, the MSD, which coincides with the VS
zero is the MSR reading.
 Example
Travelling microscope readings:

LC = 0.001 cm

Microscope Readings
Loading Unloading Depression
S. No Load (y) for
MSR TR MSR M kg
VSC VSC TR Mean
x 10-3 kg cm div cm cm div cm cm cm

1. W

2. W+50

3. W+100

4. W+150

5. W+200

6. W+250
Mean(y) = ……….cm