Name: …………………………………………………………Adm. No: ……………………..
School: …………………………………………………..…… Stream: ………………………
Candidate’s Signature:……………..… Date:………………
232 / 1
PHYSICS (THEORY)
TIME: 2 hours
BISHOP NJIRU GIRLS’ KANGETA EXAMINATION
Kenya Certificate of Secondary Education - 2025
April - August EXAMINATION
INSTRUCTIONS TO CANDIDATES
Write your name and admission number in the spaces provided above.
Sign and write the name of your school, stream and the date of the examination in the
spaces provided.
This paper consists of two sections; A and B.
Answer ALL questions in sections A and B in the spaces provided.
All your answers must be written in the spaces provided in this question paper.
All working must be clearly shown.
Silent non-programmable silent electronic calculators and KNEC mathematics table may
be used except where stated otherwise.
This paper consists of 12 printed pages. Candidates should check the question paper to
ascertain that all the pages are printed as indicated and that no questions are missing.
For Examiner’s Use Only.
Section Question Maximum Score Candidates’ Score
A 1 – 12 25
B 13 10
14 08
15 10
16 08
17 10
18 09
TOTAL SCORE
80
Page 1 of 12
SECTION A (25 MARKS)
Answer ALL questions in this section
1. A spherical ball bearing is held between the anvil and spindle of a micrometer screw gauge.
The reading on the gauge when the jaws are closed without anything between them is 0.011
cm. Use the information and the position of the scale in the figure 1 to answer questions (a)
and (b) below
25
0
20
Figure 1
(a) Determine the diameter of the ball bearing (2marks)
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(b) Determine the volume of the ball bearing in cm3. (2marks)
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2. When some common salt is put into a known volume of water, it is observed that there is no
significant change in volume of the mixture. Explain this observation. (2marks)
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3. Copper material was used to make a spring of length 10cm. state two factors that affect the
spring constant of the spring (2 marks)
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4. Highlight ONE fact that shows that heat from the sun does not reach the earth by convection
(1 mark)
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Page 2 of 12
5. Two match sticks are placed on water in a basin a few centimeters a part as shown in figure 2.
Figure 2
State and explain the observation made when a drop of soap solution is placed at a point
marked x between the match sticks. (2 marks)
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6.State and explain what happens to the stability of a non-drip candle as it continues to burn
(2marks)
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7. Figure 3 below shows a displacement – time graph.
Figure 3
Describe the motion of the body between points:
OA ................................................................................................................................... (1 mark)
AB… ................................................................................................................................ (1 mark)
8. State Newton’s second law of motion (1mark)
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9. A trolley of mass 0.5kg moving with a velocity of 1.2ms-1 collides inelastically with a second
trolley of mass 1.5kg moving in the opposite direction with a velocity of 0.2ms-1, determine
the velocity of the trolleys after collision (3 marks)
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Page 3 of 12
10. Figure 4 shows a piece of Styrofoam resting at the bottom of a transparent tube.
Figure 4
Explain what is observed when air is blown across the mouth of the tube. (2 marks)
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11. Figure 5 shows a thermometer used by a doctor to determine the temperature of a patient.
Figure 5
State the reason why it is difficult to use this thermometer (1mark)
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12. The diagram in figure 6 represents a system in equilibrium.
Figure 6
Determine the force, F needed to keep the system in equilibrium. (3 marks)
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Page 4 of 12
SECTION B (55 MARKS)
Answer all the questions in this section
13. a) An immersion heater is put into some crushed ice at 0 °C as shown in the figure 7
Figure 7
The immersion heater is switched on. The heater is left switched on after all the ice has melted,
and the temperature rises. After sometime the temperature stops rising even though the heater is
still on.
i. Suggest why the temperature stops rising, even though the heater is still on. (1 mark)
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ii.
State what happens to the heat energy received by the water whilst this is happening.
(1 mark)
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(b)Why does a scald from steam cause more harm than one from boiling water? (1mark)
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(c) Explain why water kept in a porous pot on a hot day remains cooler than that contained in a
metallic vessel (1 mark)
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Page 5 of 12
(d) 1800g of a liquid at 100C is poured into a well-lagged calorimeter. An electric heater rated
1.5kW is used to heat the liquid. The graph in figure 8 shows the variation of temperature of
the liquid with time.
Figure 8
Use the graph to answer the questions that follow:-
I. State the boiling point of the liquid (1 mark)
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II. Determine the specific heat capacity of the liquid (3 marks)
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III. If 60g of the liquid vapour was collected by the end of the 8th minute, determine
the specific latent heat of vapourization of the liquid (2 marks)
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Page 6 of 12
14. a) Figure 9 below shows a set up to investigate one of the gas laws.
mm scale
Stirrer
Conc. sulphuric
acid index
water
bath
Figure 9
Heat
i) State the gas law being investigated. (1 mark)
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ii) Give ONE reason for using the concentrated sulphuric acid index. (1 mark)
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iv) State two measurements that should be taken in this experiment. (2 marks)
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v) Describe how the measurements taken in (iv) above may be used to verify the law.(4 marks)
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Page 7 of 12
15. (a) Figure 10 shows a car of mass m moving along a curved part of the road with a constant
speed
Figure 1
State in which part A or B of the road is the car more likely to skid if the speed is not
changed (2 marks)
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(b) Given that the car in (a) above has a mass of 800kg and the circular path of radius
25m. Determine the maximum speed with which the motorist can travel so as not to skid.
The frictional force between the tyres and the road is 6500N. (3 marks)
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(c) A 200g mass tied to a string is being whirled in a vertical circle of radius 32cm with
uniform speed. At the lowest point, the tension in the spring is 10.5N. Determine:-
I. The speed of the mass (3 marks)
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II. The tension in the string when the mass is at the uppermost position of the
circular path (take g = 10ms-2) (2 marks)
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Page 8 of 12
16. a) Define velocity ratio as used in machines (1mark)
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(b) Figure 11 shows a cross-section of a handle of a screw jack 70cm long. The pitch of the
screw is 0.8cm.
Figure 11
Given that the efficiency is 65%, calculate:-
(i) The velocity ratio of the system (2marks)
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(ii) The mechanical advantage of the screw jack. (2marks)
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(e) State ONE reason why the efficiency of the machine in (b) above is less than 100%
(1 mark)
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Page 9 of 12
(f) Sketch a block and tackle system having 4 pulleys with a velocity ratio of 5. Indicate
the load and effort (2 marks)
17. a) (i) State Archimedes’ Principle. (1mark)
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(ii) An object weights 1.04N in air, 0.64N when fully immersed in water and 0.72N when
fully immersed in a liquid. If the density of water is 1000kgm-3, find the density of the
liquid. (3marks)
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(b) Give a reason why a steel rod sinks in water while a ship made of steel floats on water.
(1mark)
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Page 10 of 12
(c) Figure 12 shows a buoy, B, of volume 50 litres and mass 15kg. It is held in position in sea
1
water of density 1.04gcm-3 by a light cable fixed to the bottom so that of the volume of the
4
buoy is above the surface of the sea water.
Figure 12
Determine the tension T in the cable. (3marks)
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(d) Figure 13 shows a diagram of a hydrometer which is suitable for measuring the densities
of liquids varying between 1.2 gcm-3 and 1.8gcm-3
Figure 13
i. On the diagram indicate the label corresponding to 1.2 gcm-3 and 1.8gcm-3. (1 mark)
ii. State ONE way in which the sensitivity of the hydrometer can be improved (1 mark)
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Page 11 of 12
18. I) Figure 14 shows an instrument used to measure pressure
Figure 14
(a) Name the instrument (1mark)
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(b) Given that the atmospheric pressure is 760 mmHg and the height of mercury column in
the tube is 600 mm, determine the pressure of the air trapped in the tube in cmHg (2 marks)
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(c) State a reason why mercury is preferred for use in the above instrument (1 mark)
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(d) State what would be observed if the tube is tilted below the barometric height. (1 mark)
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(e) State and explain what will happen to the barometric height if the barometer is taken to a
place of higher altitude. (2 marks)
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(II) In an experiment to demonstrate atmospheric pressure, a plastic bottle is partially filled with
hot water and the bottle is then tightly corked. After sometime the bottle starts to get deformed.
Explain why the bottle gets deformed (2 marks)
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