PHYSICS

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 LAB. PAGE
CONTENTS
NUMBER #

To identify 5 measuring instruments (name, use, range, sensitivity &

1 uncertainty) 1-4

2 To find the density and relativity density of an object 5-8

3 To find the acceleration due to gravity using the simple pendulum 9 - 11

4 To verify Hooke’s Law with an expansion 14 - 17

5 To find the center of gravity of an irregular shaped lamina using a plumb line 18 - 20

6 To find the weight of a meter rule using the Principle of Moments 21 - 23

7 To verify the principle of Archimedes 25 - 27

8 Investigative project (Proposal) 28 – 31

9 To find the specific heat capacity, c of a piece of metal 32 - 34

10 To find the specific latent heat of fusion, l f of ice 35 – 38

11 To verify the laws of reflection 39 – 42

12 To verify Snell’s Law and find the refractive index of a rectangular glass block 43 - 47
To find the focal length of a convex lens using the lens formula
13 (1/f =1/u + 1/v) 48 - 51

14 To verify Ohm ‘s Law and find the value of an unknown resistor ‘R’ 52 - 54
15 To investigate the characteristics of a series- parallel DC circuit 57 - 59

16 To plot the magnet field around a bar magnet 60 - 63

17 Plan and design an experiment to find the acc. Due to gravity of a falling body 67 - 68
To investigate if a relationship exists between resistance and Length of a
18 resistance wire 69 – 70

19 To simulate radioactivity and determine the half-life of a sample

20 Investigative project (Execution)

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Lab #: 1

Skill: ORR

Topic: Measuring Instruments

Aim: To identify five instruments in terms of name, use, range, sensitivity, type of scale and
uncertainty

Related theory:
Measurement is a way of quantifying objects or substances; a measurement usually has
a value and a unit (e.g. 10 m). The accuracy of the measurement will also depend on the
experimenter (human), the instrument and the environmental conditions.

When choosing an instrument for a job it is important to know the data listed above.
The range is the limit of the instrument the lowest to the highest values it can take, the
smallest value it can respond to, the sensitivity; the type of scale analogue or digital,
will the response gradually change with the input or will it give digits which can be
easily read. The uncertainty, which is an estimation, the user of the instrument will have
to make if the indicator or pointer falls between the sensitivity. The user should also be
familiar with linear and non-linear scales.

List of apparatus:
1. Measuring cylinder

2. Micrometer screw gauge

3. D.C. Voltmeter

4. Triple beam balance

5. Stopwatch

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Diagram (of each instrument)

Method:
1. Gather the apparatus on the bench

2. Construct a table with the data for each column (item, name, use, range,
sensitivity type of scale and uncertainty)

3. Select an instrument and observe it carefully for the required data to complete
each column

4. Repeat the process by selecting another instrument to complete the data for the 5
instruments

Table of results

Item Name Use Range Sensitivity Uncertainty Scale type

1.
2.
3.
4.
5.

Observations: (At least 4 points here)

Discussion:
1. State which instrument seem easiest to read and why?

2. Which instrument seem most difficult to read and why?

3. Which instrument is most fragile and why?

4. Which instrument seem will have parallax error?

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 5. Which may lend itself to parallax error?

6. Which may lend itself to zero error?

Conclusion:
State your conclusion and how the aim was achieved

Reflections:

5
Lab #: 2

Skill: ORR

Topic: Measurement of density and relative density

Aim: To determine the density and relative density of a stone

Related theory:
Density is the mass per unit volume, it means how much matter or particles are in a
given volume of space.

The SI unit for density is kg m3, another common unit is g cm3.

Relative density is a ratio of the density of a substance to the density of a base substance
such as water. Relative density has no units, it is just a number, as units cancel.

List of apparatus:
1. Stone tied to a string (1)

2. measuring cylinder (1)

3. triple beam balance (1)

4. beaker with about 400 cm 3 capacity (1)

5. hand towel (1)

6. Water (as needed)

Diagram:
Draw diagrams of the weighing on triple beam balance and measuring of volumes.

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Method
1. Using the triple beam balance, weigh and record the mass of the stone.

2. Using the beaker, pour 300 cm 3 of water into the measuring cylinder and record
this volume as V 1.

3. Using the sting gently lower the stone into the measuring cylinder until it is
completely submerged and record the new volume in the measuring cylinder as
V 2.

4. Compute the volume of liquid displaced as V = (V 2 – V 1).

5. Compute the density as  = (mass)  (volume of liquid displaced), in g cm3.

6. Compute the relative density as R D = (density of stone)  (density of water).

7. Remove the stone and use the hand towel to dry the stone and repeat the
experiment.

Observations:
Record your observations (at least 4)

Discussion:
State any source of error encountered

State any precautions taken

Explain the results

Explain two ways how density differs from relative density

State any application of density or relative density

Conclusion:
State the values for the density and relative density from the experiment and anything
you may want to suggest to modify or improve in the experiment.

Reflection:
State how this experiment impacted you personally or what relevance it has on or could
have on the society.

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Lab #: 3

Skill: A&I

Topic: Measurement

Aim: To determine acceleration due to gravity using a simple pendulum

Related theory:
A simple pendulum is a small heavy body supported by a light inextensible string. A
pendulum oscillates at a regular rate and is related to acceleration due to gravity by the
𝒍
equation T = 2 π √ , where T is the periodic time, the time for one oscillation, l is the
𝒈
length, the measurement from the point of suspension of the bob to the center of the
bob, π is 3.14 and g is acceleration due to gravity.

Now, If both sides of the pendulum equation are squared, it becomes

𝒍
T2 = 4π2
𝒈

which is similar to the simple equation

𝟒𝝅𝟐
y = mx  T2 = ( )l .
𝒈

𝟒 𝝅𝟐
Here, y is equivalent to T 2, m equivalents and l is equivalent to x.
𝒈
𝟒𝝅𝟐
The variables here are l and T 2. This means that the slope of the equation, T 2 = ( )l
𝒈
will be obtained from a graph of T 2 and l.

𝟒 𝝅𝟐
Therefore, g = (will give a value for acceleration due to
𝒈𝒓𝒂𝒅𝒊𝒆𝒏𝒕 𝒐𝒇 𝒕𝒉𝒆 𝒈𝒓𝒂𝒑𝒉
gravity).

𝒈
On the other hand, if the equation is written in the form l = ( ) T 2, then the
𝟒𝝅𝟐
variables here are l and T 2.

It follows now that a graph of l versus T 2 should give a straight through the origin.

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 𝑙
From the equation above on transposing gives, g = 4 π 2 which means that means
𝑇2
𝒈
that the slope of the equation, l = ( ) T 2 will be obtained from a graph of l and T 2.
𝟒𝝅𝟐

Therefore, g = 4 π 2 × gradient of the graph (will give a value for acceleration due to
gravity).

The average value for g on earth is 9.81 m s 2.

List of apparatus:
1. Retort stand and horizontal clamp

2. simple pendulum (bob & string attached) (1)

3. Stopwatch (1)

4. G-Clamp (1)

5. metre rule (1)

6. pendulum support (1)

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Diagram:

Method:
1. Set up apparatus as shown in the diagram.

2. Set the length of the pendulum at 90 cm.

3. Set the pendulum in motion with a small amplitude, less than 15 degrees.

4. Using a countdown method time 10 oscillations.

5. Record the length and time for the 10 oscillations.

6. Adjust the length to 80, 70, 60, 50, 40 and 30 cm and for each new length time
10 oscillations.

7. Record the length and time for each new length to have a table of at least 6
trials.

8. Compute the periodic time T and T 2 for each trial.

9. Convert each length, in centimetres, to metres.

10. Plot a graph of l vs T 2

11. Determine the slope (gradient) of the graph.

12. Multiply the slope by 4 π 2 to give the value for g.

Table of results:

Trials l /cm l /m T10 /s T /s T 2/s2

1
2
3
4
5
6

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Discussion:
1. State two possible sources of error in this experiment which could affect the
accuracy

2. State two precautions which taken which could improve the accuracy of the
experiment

3. State any trend observed in the table

4. State the relationship observed on the graph

5. Comment on the accuracy of the result achieved compared to the standard value
of 9.81 m s 2 for g.

6. Comment on the relationship between l & T and l & T 2.

Conclusion:
State the result achieved and any important suggestion for future improvement.

Reflection:
State how the experiment affected you or impact society.

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Lab. #: 4

Skill:

Topic: Force (Hooke’s law)

Aim: To verify Hooke’s law and to determine the spring constant of an expansion spring.

Related Theory:
Hooke’s law states that ‘The extension of an elastic body such as a spring or wire is
directly proportional to the stretching force, if the elastic limit is not exceeded’.
Hooke’s law means as load increases then extension will also increase. This law also
means if a graph of extension is plotted against load the graph will yield a straight
through the origin. The stiffness of a spring is called the spring constant and it is given
by the equation, spring constant = load /extension (N m –1). Each elastic body has its
own spring constant, k.

List of apparatus:
1. Expansion spring (1)

2. Retort stand (2)

3. Horizontal clamps (2)

4. Pivot or spring support (1)

5. Half-meter rule (1)

6. weight hanger with pointer attached (1)

7. Standard masses 50 g each (7)

8. G clamp (2)

Diagram:
Draw a neatly labelled diagram of the setup of apparatus (2 dimensional)

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Method:
1. Set up the apparatus as shown

2. With no load attached record the position of the pointer as l o /cm.

3. Attach one 50 g mass (0.5 N) and record the new position of the pointer as l f
/cm

4. Compute and record the extension of the spring, that is, extension, e = l f – l o)
/cm

5. Repeat steps 3 and 4 for the other masses but each time remove the loads to see
if the spring returns to its original position of l o.

6. Complete the table with at least 6 trials.

7. Compute the spring constant for each trial and record it in the table.

8. Plot a graph of extension versus load and draw the best fit line.

9. Determine the slope of the graph, in cm N 1.

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10. Calculate the spring constant, k = , in N cm 1.
slope

Table of results

Trials l o /cm l f /cm e /cm Mass / g Load /N S k = l/ e (N cm 1)

1
2
3
4
5
6

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Sample calculations:
Extension = l f – l o = ________ cm

Load = force = weight of mass = m g = (50 / 1000) = ______N

Spring constant, k = load/ ext. = ______ N/cm (by definition)

𝑦2 − 𝑦1
Slope = = _______ cm N–1
𝑥2 − 𝑥1

1
k from extension versus load graph = = ________ cm N–1
slope

Discussion:
1. State TWO sources of error.

2. State precautions taken.

3. State the trends seen in the table.

4. State the relationship observed from the graph.

5. Suggest any modification.

6. State any application of Hooke’s Law

Conclusion:
State how Hooke’s Law was verified and the spring constant with the units.

Reflection:

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Lab#: 5

Skill: ORR

Topic: Center of gravity

Aim: To find the center of gravity of an irregular shaped lamina

Related theory:
Center of gravity is the point associated with an object where all the weight seem to act
for all orientation. It is the point where the object will balance or be in equilibrium. The
position of the center of gravity determines the stability of an object, when the center of
gravity is high the object will be more unstable and if it is low it will be more stable.

There are three types of equilibrium, neutral, stable and unstable; neutral equilibrium (a
ball) the height of the center of gravity does not change when the object is disturbed,
with unstable equilibrium (a cone on its point) the center of gravity falls when the
object is disturbed and the object usually falls and stable equilibrium (a cone on its
base) the center of gravity rises when it is disturbed but it falls back into place. Objects
usually are more stable if they have a broad base and if they are very dense.

The center of gravity of regular geometric shapes such as rectangles, cones, triangles,
circles can be found be at the intersection of diagonals, medians and center lines. The
center of gravity of irregular shapes are found at the intersection of plumb lines or
balance lines from knife edges.

Material and apparatus:

An irregular shaped lamina with three to four holes near the edge

A plumb line

A pivot on which the lamina can hang freely

A sharp pencil

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Diagram:

Method:
1. Cut a piece of cardboard in an irregular shape and bore 3-4 holes at a fair
distance apart near the edge.

2. Hang the lamina at the pivot and allow it to swing freely as shown.

3. Hang the plumb line at the pivot and allow it to swing freely.

4. When the plumb line and lamina are steady mark two points along the line, one
near the pivot and one near to the edge of the lamina.

5. Remove the plumb line and the lamina and using the 30 cm rule and pencil draw
a straight line to connect the points.

6. Repeat the process for the other holes.

7. Test the balance by placing it on the fingertip at the point of intersection.

Results:

Observations:
List four (4) observations.

Discussion:
List four (4) possible sources of error in this experiment.

Precautions:

List four precautions taken

Explain the results.

State TWO instances of how center of gravity is applied in society.

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Conclusion:

Reflection:

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Lab#: 6

Skill: M&M

Topic: Turning force (Moments)

Aim: To find the weight of a meter rule using the principle of moments.

Related theory:
Moments is the product of force and perpendicular distance from a pivot. In this
experiment a 1N force is used to balance the weight ‘W’ of the meter rule. The pivot is
placed between the 1N force and the weight, ’W’ of the meter rule. The position of the
weight of the meter rule was previously found by balancing it on the pivot.

When balance is achieved on the pivot the 1N force generates an anti-clockwise

moment about the pivot and the weight of the meter rule ‘W’ generates a clockwise
moment about the pivot to keep the system steady. If the principle of moments is
applied then ‘W’ can be calculated from the equations below.

Anti -Clockwise moment = Clockwise moments (when the meter rule is steady)
It then follows that 1N x d 1 = W  d 2
𝑑1
From which W = 1N  .
𝑑2
Alternatively, if a graph of d 1 versus d 2 should yield a straight line through the origin
and the gradient should give the weight of the rule ‘W’.

List of Apparatus:
1. Meter rule

2. Mounted pivot

3. 100 g mass (1 N force) fitted with a loop (1)

4. Work bench

Set up Diagram:

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Method:

1. Place the meter rule on the pivot and slide it until it is balanced (level and
steady).

2. Record the position of the center of gravity, where ‘W’ acts.

3. Set up the apparatus as shown in the diagram.

4. Starting with the ‘1 N’ hanging at the 2 cm mark slide the meter rule slowly
until it balances.

5. Record the distances d 1 (B-C) and d 2 (C-B).

6. Repeat the process with new positions for the 1N force e.g. 4 cm, 6 cm, 8 cm
etc. for at least six trials

𝑑1
7. Complete the table for the six trial with the calculation for ‘W’ as  (N)
𝑑2

8. Find an average of the values off of ‘W’ and record this value in N.

9. Alternatively, plot a graph of d 1 versus d 2, draw the best fit line and then
calculate its gradient to give the value for ‘W’ in N.

Table of result
Trials Pos. of c of g Pos. of pivot Pos. of 1 N d1 d2 𝑑1
W=( )
cm cm force /cm (B-A)/cm (C-B) /cm 𝑑2
N
1
2
3
4
5
6
7

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Calculations:
d 1 = position of pivot - position of 1 N
=

d 2 = Position of weight ‘W’ – position of pivot

=

Average of d1/d2 gives a value for ‘W’ = ________

Gradient of best fit line of graph of d 1 vs d 2 also gives a value for ‘W’
𝑦2 − 𝑦1
= = _________
𝑥2 − 𝑥1

Discussion:
State two possible sources of errors in the experiment and suggest a precaution to
eliminate or minimize them.

List two reasons why the ruler stayed steady when balanced at the pivot.

What trend is seen in the table for the values of d 1 and d 2.

State the relationship produced by the graph of d 1 versus d 2.

State two applications of the principle of moments.

Conclusion:

Reflection:
Write a few sentences.

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Lab #: 7

Skill: M&M

Topic: Buoyant Force

Aim: To verify Archimedes Principle

Related Theory:
Archimedes Principle states that, if a body is wholly or partially immersed in a fluid it
experiences an apparent loss in weight as a result of the up thrust of the fluid and this up
thrust is equal to the weight of the fluid displaced.

Interpretation of Archimedes Principle

The Principle means
Weight in air - weight in fluid = up thrust
Up thrust = weight of fluid displaced = mg = Ρ V g (since ρ = m / V then, m = ρ V)

List of apparatus:
Measuring cylinder (1)
Retort Stand (1)
Horizontal clamp (1)
Spring balance (0-10N) (1)
Weight holder (1)
Standard masses (100g each) (5)
G Clamp (1)

Method:
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 1. Pour 300 cm3 of water in the measuring cylinder and record it as V 1 /cm 3.

2. Weight and record the 5 standard masses with the spring balance and record it as
WA

3. Gently lower the 5 masses into the water until they are completely submerged

4. Record the new volume of water as V2 and the new weight of the 5 standard
masses as WW

5. Compute the volume of water displaced

VDP = (V2 –V1) cm3

6. Compute the weight of the water displaced by the 5 masses (Weight of water
displaced, WDP = ρ V g) in N

7. Compute the up thrust of the water, as up thrust, U = WA – WW

8. Compare the weight of water displaced with the up thrust, U.

9. Repeat the experiment using 400cm3 of water and after drying the 5 standard
masses with a hand towel.

Weighing & measurements

Volume of water =
Volume with masses submerged =
Weight of masses in air =
Weight of masses in water =
Calculations:
Trial 1

V = V2- V1

U = W Air – W in water

W water displaced = ρ V g

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 Trial 2
V = V2 - V1

U = W in Air – W in water

W water displaced = ρ V g

Discussion:
List two possible sources of error in the experiment and two precautions taken to
minimize them.

How did the weight of the displaced water compare with the up thrust? Was
Archimedes Principle verified? Explain.

Briefly explain how does; a floating body; a submerged body and a sunk body are
influenced by up thrust and the weight.

Explain how does density of a fluid affects its up thrust?

Conclusion:
State your conclusion of the experiment.

Reflection:

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Skill: P&D

Topic:

Observation:

Hypothesis:

Aim:

Material and apparatus:

Diagram:

Method:

Variables:

Expected Results:

Assumptions /precautions/possible errors

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Lab# 8

Skill: M&M

Topic: Heat transfer

Aim: To find the specific heat capacity of a piece of metal using the method of mixtures.

Related Theory:
Specific heat capacity, c, of a substance is the amount of heat required to raise the
temperature of 1kg of a substance by 1 degree. Each and every substance requires a
different amount of heat to raise its temperature by 1 degree.

The method of mixtures is based on the law of conservation of energy and suggest that
when bodies of different temperatures are mixed, the heat energy lost by one body is the
heat gained by others. In this experiment a heated piece of metal and tap water are
mixed. The heat lost by the heated metal is gained by the tap water and its containers.
The specific heat capacity of the metal, cm, will be calculated from the formula (m c
ΔT) metal = (m c ΔT) water, assuming that the heat is absorbed by the container is
negligible. From the equation, c metal = (m c ΔT) water / (m ΔT) metal

Materials and supplies:

Piece of metal tied to a string (1)

Triple beam balance (1)

Thermometer (1)

Heating pot (1)

Styro-foam cup (1)

Electrical heater (1)

Diagram of setup:

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Method:
1. Weigh and record the mass of the metal

2. Weigh and record the mass of the empty cup

3. Half fill the cup with tap water and weigh and record its mass

4. Measure and record the temperature of the tap water

5. Heat the metal in the heating pot for about five minutes at about 500 degrees

6. Measure and record the temperature of the heating water of the metal

7. Using the string jerk water free of the metal and quickly transfer it to the water

8. Stir the water gently and record the steady temperature

Results:
Taking measurements: weight
Mass of metal, m m =

Mass of empty cup, m c =

Mass of cup and water, m ( c + w) =

Mass of water, m w = ?

Taking measurements: temperature

Initial temperature of water,  1 =

Final temperature of mixture,  f =

Initial temperature of metal,  m =

Temperature change of mixture, T w =  f   1 = ?

Temperature change of mixture, ΔT m =  m   f = ?

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Calculations:
m w = m ( c + w)  m c =

T w = f  1 =

ΔT m =  m   f =

𝑚𝑤 × 𝑐𝑤 × ∆𝑇𝑤
cm = =
𝑚𝑚 × ∆𝑇𝑚

Discussion:
State TWO possible errors.

State TWO precautions.

State how accurate was the experiment.

Explain how the value of specific heat capacity affects thermal conduction.

State TWO applications of specific heat capacity.

State an assumption made in the experiment.

Conclusion
Predict the name of the metal

Reflection:

27
Lab # 9

Skill: M&M

Topic: Latent heat (Change of state)

Aim: To find the specific latent heat of fusion of ice using the Method of Mixtures

Related Theory:
Latent heat is hidden heat energy, it is the heat used to break the bonds or form the
bonds of a substance as it goes through a change of state. Specific latent heat of fusion,
lf, of ice is the amount of heat energy needed to change 1kg of ice to water without any
change in temperature. This heat is not indicated by the thermometer, this means the
temperature remains at zero degrees until the ice - water change of state is complete.

In this experiment the heat from tap water is used to melt a cube of ice and then raise its
temperature to the final temperature of ice water and tap water mixture.

Therefore, using the method of mixtures it follows that the

Heat lost by tap water = Heat used to melt the ice + raise the temperature of the ice
water to the final temperature of the mixture.
(m c ΔT) tap water = (m lf ) ice + (m c ΔT) ice water

(𝑚 × 𝑐 × ∆𝑇)𝑡𝑎𝑝 𝑤𝑎𝑡𝑒𝑟 − (𝑚 × 𝑐 × ∆𝑇)𝑖𝑐𝑒 𝑤𝑎𝑡𝑒𝑟

lf =
𝑚𝑖𝑐𝑒

Diagram:

Results:
Taking measurements: weight
28
 Mass of empty cup, m c =

Mass of cup and water, m ( c + w) =

Mass of cup and water, m ( c + w + ice) =

Mass of water, m w = ?

Mass of water, mw = m ( c + w)  m c = ?

Taking measurements: temperature

Initial temperature of water, T 1 =

Initial temperature of ice water, T 2 =

Final temperature of metal, T 3 =

Change in temperature of water, ΔT water = ?

Change in temperature of ice water, ΔT ice water = ?

Calculations:
m w = m ( c + w)  m c =

m(c + w + ice)  m ( c + w) =

Δ T water = T 1 – T 3

ΔT ice water = T 3 – T 2

(𝑚 × 𝑐 × ∆𝑇)𝑡𝑎𝑝 𝑤𝑎𝑡𝑒𝑟 − (𝑚 × 𝑐 × ∆𝑇)𝑖𝑐𝑒 𝑤𝑎𝑡𝑒𝑟

lf = =
𝑚𝑖𝑐𝑒

29
Discussion:
List THREE possible sources of error

State the precautions taken to reduce these errors

State ONE application of specific heat capacity

Specific heat capacity of a material affects the thermal conductivity, Explain.

Conclusion:

Reflection:

30
Lab# 10

Skill:

Topic: Reflection of waves

Aim: To verify the laws of reflection

Related theory:
Reflection is the bouncing of a wave from a surface
Regular reflection occurs at a smooth surface such as a plane mirror. Irregular reflection
occurs at a rough or uneven surface such as a bench top. The laws of reflection states as
follow
Law 1 ‘the incident ray the reflected ray and the normal at the point of incidence all lie
in the same plane’
and
Law 2 states ‘ the angle of incidence is equal to the angle of reflection’.

List of apparatus:
Pin board (1)

Blank sheet (1)

Pins (4)

Protractor (1)

30 cm ruler (1)

Pencil (1)

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Diagram:

Method:
1. Gather the apparatus as listed.

2. Secure the blank sheet to the pin-board with the tape.

3. Draw the mirror line MM in the top third of the paper.

4. Construct a normal N in the middle of MM.

5. Draw the incident ray as line AO at a suitable angle say 20 degrees.

6. Record the angle of incident AON in a table.

7. Stick two pins P1P2 on the line AO at fair distance apart.

8. Align P3P4 (reflected ray) with the images of P1 and P2 (incident ray).

9. Remove the pins P3P4 and the mirror, then join P3P4 to form the reflected ray
OB.

10. Measure and record the angle of reflection NOB.

11. Compare angle AON with NOB.

12. Repeat step 5-11 for four more angles of incidence.

32
Table of result:

Trials i /deg. r /deg.

1

4
5

Discussion:
List two possible sources of errors

State two precautions

State any limitations

Comment on the results

State two applications of plane mirrors

Conclusion:
State how law 1 was verified

State how law 2 was verified

Reflections:

33
Lab# 11

Skill: A&I

Topic: Refraction of waves

Aim: To verify the laws of refraction and find the refractive index of glass.

Related theory:
Refraction is the change in speed of a wave as it passes from one medium to the next.

The laws of refraction states:

Law 1: ‘The angle of incidence and the angle of refraction are on opposite sides
of the normal

Law 2: ‘The ratio of the sine of the angle of incidence to the sine of the angle of
refraction is a constant for a pair of optical media.

𝐬𝐢𝐧 𝒊
The ratio = n,
𝐬𝐢𝐧 𝒓

where n is the refractive index of the second medium.

The equation above can be written as

sin i = n sin r
which is similar to
y = mx

Hence, a graph of sin i versus sin r should yield a straight line through its
origin, the gradient of the graph should give the constant n.

34
List of apparatus:
Pin-board (1)

Blank sheet paper (1)

Protractor (1)

pins (4)

30 cm rule (1)

Pencil (1)

Tape (1)

Set up diagram:

Method:
1. Gather the apparatus as listed.

2. Secure the blank sheet to the pin-board with the tape.

3. Draw the outline of the glass block and label the corners ABCD.

4. Remove the glass block and construct a normal NON’ in the middle of AB to
meet AB at O.

5. Draw the incident ray as line PO at a suitable angle say 20 degrees.

6. Record the angle of incident PON (angle i) in a table.

7. Press two pins P1P2 on the line PO at fair distance apart.

8. Replace the block on the outline.

9. From the opposite side of the block CD, align two other pins P3P4 with the
images of P1P2
35
 10. After proper alignment Join the points P3P4, the emergent ray EG to meet AB at
T.

11. Join TO which gives the refracted ray.

12. Measure and record angle of refraction TON (angle r).

𝐬𝐢𝐧 𝒊
13. Compute the values of sine i, sine r and n = and record in the table.
𝐬𝐢𝐧 𝒓

14. Repeat the steps 5-13 for other angles of incidence and complete a table with at
least 6 trials, for each trial the rectangular block should be replaced in the same
spot.

15. Plot a graph of sin i versus sin r and draw the best fit line.

16. Compute the gradient to give a value for n the refractive of glass

17. Observe the angle of incident, the normal and the angle of reflection for law 1.

18. Observe the ratio of the sine of the angles of incidence to the sine of the angles
of refraction for law 2.

Table of results:

𝐬𝐢𝐧 𝒊
Trial Angle i / Angle r / sin i sin r n =
𝐬𝐢𝐧 𝒓
1
2
3
4
5
6

Calculations/Graph:

Sample calculation:

sin i = ___________

36
 sin r = ___________

n = ___________

𝑦2 − 𝑦1
Gradient = = _____________
𝑥2 − 𝑥1

Discussions:
State two (2) possible sources of error.

List two (2) precautions taken.

State a limitation encountered.

Explain two ways (2) in this experiment of finding an average value for n.

Comment on the value for n from the graph and the table.

State the relationship expressed by the graph of sin i versus sin r.

State one (1) application for refractive index.

Conclusion:

Reflection:

37
Lab # 12

Skill: ORR

Topic: Ray Optics

Aim: To find the focal length of a convex lens by using the lens formula 1/f = 1/u +1/v

Related Theory:
The focal length is the distance from the center of the lens to the principal focus. The
principal focus is that point on the principal axis to which rays originally parallel and
close to it will converge to after undergoing refraction through the lens. When the
image of an object is formed by a convex lens, the object distance, u is measured from
the center of the lens to the object and the image distance, v is measured from the center
of the lens to the image.

The mathematical relationship between f, u, and v is given by the equation

1 1 1
= +
𝑓 𝑢 𝑣

From the equation above, the focal length would be transposed as:

𝑢 × 𝑣
f = .
𝑢+ 𝑣

In this experiment the apparatus is arranged to so that a convex lens will produce
images of various sizes of a cross wire object.

38
 The object distance u and image distance v can be measured from which the focal
length, f, can be computed from the formula stated above.

List of material:
White screen

Mounted convex lens

light box with a cross wire as the object

Meter rule secured to the bench

Diagram:

Method:
1. Set up the apparatus as shown in the diagram.

2. Construct a table with the headings; trials, u /cm, v /cm, u v /cm 2, (u + v) cm

𝒖 × 𝒗
and f = /cm.
𝒖+ 𝒗

3. Adjust the screen until an image of the cross wire appears on it.

4. Slide the screen slowly until the sharpest image of the cross wire is seen on the
screen.

5. Measure and record the distances of u and v.

6. Adjust the screen or the lens so that the distances for u and v can be measured
for at least three small and three large images.

39
 7. Use the values of u and v for each trial to compute a value for f.

8. Complete the table for 6 trials.

9. Compute the average, f, for the six trials for the focal length of the lens.

Results:

𝒖 × 𝒗
Trial Size of image u /cm v /cm u v /cm 2 (u + v) /cm f = /cm
𝒖+ 𝒗

1 Big
2 Big
3 Big
4 Small
5 Small
6 Small
Average f =

Discussion:
State three (3) possible errors in this experiment.

State three (3) precautions taken to overcome or minimize the errors mentioned.

State any limitation encountered.

Explain why some images are large and some are small

State TWO (2) applications for foal length

Conclusion:
State the focal length and any modification to the experiment you could suggest.

Reflection:

40
Lab# 13

Skill: A&I

Topic: Electricity-Ohm’s Law

Aim: To verify Ohms Law and find the value of an unknown resistor ‘R’

Related Theory:
Ohm’s Law states ‘the current in an electrical conductor I, is directly proportional to the
voltage V, across it and inversely proportional to the resistance R, provided the
temperature remains constant’ Ohm’s Law means as the current increases then the
voltage also increases and that as current increases the resistance decreases. The current,
voltage (potential difference) and resistance are related by the equation

V = IR

and so

𝑽
R = .
𝑰

Graphically, if a graph of voltage versus current is plotted for an Ohmic device, then the
graph will yield a straight line through its origin and the gradient of that graph will give
the resistance of the device.

If Voltage versus Current graph is plotted for an Ohmic device, that too will yield a
straight line through the origin and the resistance will be determined as

R = slope of that graph (gradient).

41
List of Apparatus:
Unknown resistor

Power supply (0- 15V) (1)

Ammeter (0-50mA, 0-500mA) (1)

Voltmeter (0 - 15V) (1)

variable resistor (0 - 80 Ohms) (1)

Single pole switch (1)

Pairs of alligator clips (7)

Circuit Diagram:

Method:
1. Set up the circuit as shown, with the switch open and set the rheostat at mid –
point.

2. Close the switch, read and record the ammeter and voltmeter values.

3. Check to see that the unknown resistor is not over heating.

4. Adjust the rheostat for higher or lower values of current and voltages then read
and record these values in the table shown.

42
 5. Repeat steps 3 - 4 to complete the table with at least six pairs of current and
voltage.

6. Compute the resistance for each pair of current and voltage from the formula
𝑽
R = .
𝑰

7. Plot a graph of voltage versus current and draw the best fit straight line.

8. Determine the slope of the line to give the average value of the unknown resistor
‘R’.

Table of Results
𝑽
Trials I /mA I /A V /V R = /Ω
𝑰
1
2
3
4
5
6
7

Calculations:
Sample of each type.

______ mA = ______ A

𝑉
R = = ______ 
𝐼

Graph:

Discussion
State TWO possible sources of errors explain how they may be minimized.

43
 State ONE precaution taken for safety of the unknown resistor.

Identify any trends observed in the table.

State the relationship seen from the graph between V and I.

If a resistor of resistance 20 kΩ has a voltage supply 15V. What is the current flowing
through it in milli-Amperes.

State ONE applications of Ohm’s Law.

Conclusion:

Reflections:

44
Lab#: 14

Skill:

Topic: DC Circuits- Series-parallel

Aim: To investigate the characteristics of a series parallel circuit

Related theory:
A series parallel circuit is a combination of a series and parallel circuit, that is, it has main and
branches. The current in the main is constant but it divides in the branches. The total voltage in the
series- parallel circuit divides among the series and parallel parts.

List of materials:
dc power supply (1)

dc ammeters (3)

dc voltmeters (3)

single pole switch (1)

pairs of alligator clips (8)

carbon resistors (2)

Diagrams:

45
Method:
1. Construct 2 tables with the headings I T , I s1, I p1, I p2, I s2 and V T, V s1, V p, V s2,
as shown below.

2. Check all meters for zero error and do any necessary adjustment.

3. Construct circuit 1 with the switch left open.

4. Have your instructor recheck the circuit and then close the circuit.

5. Read and record the current values for I T, I 1, and I 2.

6. Construct circuit 2 with the switch left open

7. Have your instructor recheck it and then close the switch

8. Read and record the voltage values for V T, V s1, V p, V s2.

9. Observe the tables and make your analysis for current ad voltage in the series-
parallel circuit.

Table of results:

IT /mA Is1 /mA IP1 /mA IP2 /mA IS2 /mA VT/ V VS1 /V VS2 /V VP1 /V VP2 /V

Table 1 table 2

Calculations:
Finding
IT = I main = IS1 + IP1 + IP2 + IS2 = _____

Finding
VT = VS1 + VP + VS2 = __________

46
Discussion:
State two possible sources of error in the experiment.

State two precautions in the experiment.

State one characteristic of a series circuit

State one characteristics of a parallel circuit.

State two characteristics of a series-parallel circuit.

Conclusion:

47
Lab#: 15

Topic: Mag

Aim: To plot the magnetic field around a bar magnet

Theory:
A magnet is a material attracted to iron, nickel cobalt or an electromagnet. A magnet
has a north seeking and a south seeking pole. The region around a magnet where a
magnetic force is felt is called the magnetic field. Magnetic field lines leave at the north
end and re-enter at the south.

A plotting compass is a steel needle encased between two glass faces and allowed to
oscillate on a pivot. It is a permanent magnet which aligns itself with the magnetic field.
A plotting compass can be used to plot a magnetic field.

List of apparatus
Bar magnet (1)

Blank sheet of paper (1)

Plotting compass (1)

Sharp pencil (1)

Masking tape

Flat surface or table (1)

Diagram: (draw the diagram)

48
Method:
1. Collect the apparatus

2. Secure the blank sheet to the flat surface and mark a 1cm border line around it

3. Outline the bar magnet in the center of the sheet

4. Mark the poles of the magnet north (red) and south (blue)

5. Place the plotting compass near to one pole of the magnet and plot the point of
the compass farthest away from the magnet

6. Slide the compass away until the plot is aligned with the opposite end of the
compass and plot the point farthest away again

7. Continue to plot until a loop is complete or a the border is reached

8. Connect the plots to draw in a smooth loop or curve

9. Plot at least 6 loops, 3 on each side of the bar and at least 4 at each end of the
bar magnet.

Results:

(Place your sheet here)

49
Observations:
State, at least, 4.

Discussion questions:
What is the shape of the magnetic field?

What is the direction of the magnetic field in respect of north and south, explain?

Which end of the compass was attracted to the north end and to the south end of the bar
magnet, respectively?

State the law of magnets.

State two applications of bar magnets.

Conclusion:

Reflections:

50
Lab#:

Skill: P&D

Topic: Acceleration due to gravity

Observation:
John saw his friends warming up for a cricket games and as they did so they tossed the
cricket ball high and ran to catch it. He commented, that is a falling body which is
influenced by acceleration due to gravity. It may be possible to find the acceleration due
to gravity of a falling body for my project.

Hypothesis:
The distance travelled by a body with uniform motion is given by the equation
𝟏
s = ut + g t 2.
𝟐

If the body falls vertically then u = 0. Therefore, the equation is reduced to

𝟏
s = g t 2.
𝟐

From the equation above, the acceleration due to gravity will be transposed as

𝟐𝒔
g = .
𝒕𝟐

So, if the distance s is known and the time t is known, g can be found mathematically.

Graphically, if a graph of s versus t 2 is plotted, it should yield a straight line through its
origin. So the equation

𝟏
s = g t 2 is of the form y = m x.
𝟐

It then follows that the

gradient of that line = ½ g.

51
 Therefore,

𝑔 𝒔.
= slope =
2 𝒕𝟐

𝟐𝒔
From the above graph, hence, g = 2 × slope or .
𝒕𝟐

Aim:
To find acceleration due to gravity of a falling lawn tennis ball

Variables –
The distance, s, and the time, t.
Constant –
The mass of the ball and acceleration due to gravity, g.

List of apparatus:
Lawn tennis ball (1)

Steel tape (1)

Stop watch (1)

Wall of reasonable height

Method:
1. With the aid of the steel tape and pencil, measure, mark and record various
heights from which to release the ball along the wall. These heights should be a
fair distance apart.

2. Have your partner release the ball and using the stop watch and a countdown
technique to time each drop.

3. Repeat this process for at least six different heights.

4. Square the time for each height and record this time.

5. Plot a graph of s versus t 2 and draw the best fit straight then determine the slope
of the line.

52
 6. Calculate the acceleration due to gravity, g = 2 × slope.

Expected result

𝟐𝒔
Trial Distance, s /m Time of drop, t /s t 2 /s2 g = /m s2
𝒕𝟐

2
3
4
5
6
7
Average =

Calculations or graph:
Sample calculations
t2 = t  t = ____________
𝑦2 − 𝑦1
Slope = = _________
𝑥2 − 𝑥1

2𝑆
g= = ____________
𝑡2

Average, g = ____________

Or
By graph
𝑔
Plot a graph of s versus t 2 and the gradient will give , therefore g = 2 slope.
2

Assumptions/precautions/source of error and limitations:

Assumption: It is assumed that the ball falls vertically.

Source of error: parallax error when reading the steel tape and reaction time when
releasing the ball.

53
Precaution taken: The countdown was used to reduce reaction time error.

Limitations: The height from which the object can be dropped.

The instrument to measure extreme heights for more than say 40 m

54
Lab#

Skill: P&D

Topic: Electrical resistance

Problem statement
A boy who does Electrical Technology suggests that there is a direct relationship
between the resistance of a piece of wire and the length.

Plan and design an experiment to investigate if a relationship exist between the

resistance R and the length L of a piece of wire.

Hypothesis
The resistance of a piece of wire is given by the formula

𝒍
R=ρ
𝑨

where R is resistance, ρ is the resistivity of the wire, l is its length and A is its cross-
sectional area.

If ρ and ρ are constant, then R is directly proportional to l, as the equation above is

similar to y = m x then a graph of R versus l should yield a straight line through the
origin.

Aim: To investigate the relationship between R and l for a piece of wire.

Variables: R and l
Constants: A and ρ

55
Materials and supplies

DC supply 0-5V (1)

Single pole switch (1)

DC Voltmeter (0-5 v) (1)

AC Ammeter (0-500mA) (1)

Meter rule (1)

Piece of nichrome wire (1)

Diagram:

Method:
1. Set up the circuit as shown with the switch left open with the power supply set at
3V.

2. Close the circuit, and record the length, current and voltage values.

3. Adjust the length and record the new values of length, voltage and current.

4. Repeat the experiment for at least six sets of values, the lengths should be at a
fair distance apart.

5. Compute and record a value for R for each trial.

6. Plot a graph of R versus l and draw the best fit line to observe if a relationship
exists.
56
Expected results

𝑽
Trials l /cm I /mA I /A R = (Ω)
𝑰
1
2
3
4
5
6

Assumptions:
All instruments are properly calibrated

The lengths are read inline

The supply voltage is constant throughout the experiment

The wire is not overheated

Precautions/limitations/ precautions
Check all instruments for zero error and do the necessary corrections

Read all meters in line with the scale to avoid parallax error

57
Lab#

Skill: P&D

Topic: Radioactivity and half-life

Problem statement:
A school does not have any radioactive material to demonstrate the process
radioactivity or half-life to the students. Plan and design an experiment to simulate
radioactivity and find the half-life of a sample

Hypothesis:
Radioactivity is the spontaneous decay of an unstable atom with the emission of
particles and energy.

Radioactivity is a random process, that is, one never knows which particle will be
emitted at any time.

The rate of decay depends on the amount of particles present.

A radioactive sample can generate a decay curve from which its half-life can be
determined.

Half-life is the time taken for a sample to decay to half the original amount or activity.

In this experiment, the sample is 80 dies in a container, the particles to decay are any six
facing up when the container is emptied on a flat surface. The half-life will be taken in
terms of throws, that is the number of throws for the sixes facing up to decay from 80 to
40, 40 - 20, 20 - 10, 10 - 5 and so on.

Aim: To simulate radioactivity and find the half-life of a sample of 80 dies

Materials required
80 similar dies

A container for the dies

A large flat surface to throw the dies

58
Variables: Number of throws and amount of sixes remaining
Constants: Size of dies, surface on which they are thrown

Diagram:

Method:
1. Construct a table with the headings; Throws, Initial # of sixes, # of sixes
removed, # of sixes remaining.

2. Count the number of dies and place them into the container.

3. Throw the dies on to the flat surface.

4. Pick out all the sixes facing upward and record this amount in the table.

5. Record the number of throws, number of sixes facing up and those which
remain.

6. Repeat the throw process, each time picking out the number of sixes facing up
and computing the amount remaining and then record the information in the
table.

7. Do at least five trials or until the sixes facing up reduce to one.

8. Plot a graph of number of sixes remaining versus throws.

9. Determine the half- life in throws at the amounts remaining of 40, 20, 10 and 5.

10. Find the average half-life in throws TO REPORT AS AN ANSWER.

59
Expected Results

Throws Initial # of sixes # of sixes rem Amount of sixes rem

1 80

3
4
5
6

Typical decay curve

with one half- life shown.

Assumptions:
The dies are identical

The surface is uniform

No die falls on its edge

The throws are made with equal force

Limitations:
The number of dies

To make all throws with the same force

Precautions:
Ensure all dies fall on flat surface

Ensure an accurate count

60