KCSE 2024 Physics Paper 2 Questions and Answers
KCSE 2024 Physics Paper 2 Questions and Answers
This page contains the official KNEC KCSE question papers and marking schemes from the 2024 KCSE examination. Below, you will find the complete set of questions as they appeared to candidates in the exam hall, followed by the official marking scheme used by examiners. Use these authentic KCSE past papers and answers to practice under the real KCSE exam conditions and effectively revise for the KCSE examinations.
SECTION A
Question 1/18
Figure 1 shows the image formed by a plane mirror when an object is placed in front of the mirror.
Apart from the image being virtual and of the same size as the object, state one other characteristic displayed in the figure. (1 mark)
Question 2/18
A student observed that when removing a polyester sweater, a cracking sound was produced. Explain this observation. (2 marks)
Question 3/18
Explain what happens to the potential difference of a charged parallel plate capacitor when the distance of separation between the plates is reduced. (3 marks)
Question 4/18
State one advantage of using a circuit breaker instead of a fuse in a domestic wiring system.
Question 5/18
A student is provided with a steel needle and a copper coin. Describe how the student can use a bar magnet to identify which of the two materials is magnetic. (2 marks)
Question 6/18
Figure 2 shows an object ‘O’ and its image ‘I’ as formed by a concave mirror.
Complete the ray diagram and indicate the focal length of the mirror. (2 marks)
Question 7/18
Using domain theory, explain how electric current produces a magnetic effect in an electromagnet. (3 marks)
Question 8/18
State the meaning of the term periodic time of a wave. (1 mark)
Question 9/18
Explain why sound energy travels faster in a metal block than in water. (2 marks)
Question 10/18
State the meaning of the term refractive index of water. (1 mark)
Question 11/18
Figure 3 shows a cell connected to a bulb and a switch.
When the switch is closed, the bulb lights. Explain how the cell drives the electrons in the circuit. (2 marks)
Question 12/18
An electric bulb is marked 60 W, 240 V. Determine the energy the bulb consumes in one minute.
Question 13/18
(a) State what is meant by long-sightedness as an eye defect. (1 mark)
(b) Explain how long-sightedness can be corrected using a lens. (2 marks)
SECTION B
Question 14/18
(a) Figure 4 shows an electromagnet set-up.
When the magnet is moved towards the coil, as shown by the arrow, the milliammeter reads a maximum current of 0.1 mA.
(i) Explain how the current is generated in the circuit. (3 marks)
(ii) Using the same set-up, state how the current observed in the milliammeter can be increased. (1 mark)
(iii) On the figure, indicate with an arrow the direction of the induced current in the coil. (1 mark)
(iv) Explain why the current flows in the direction shown in part (iii). (3 marks)
(b) A family observed that after purchasing a refrigerator, the monthly electricity bill increased by Ksh 2000 in a 30-day month. Given that the cost of electricity per kWh is KSh 4.00 and the fridge was used for 24 hours per day, determine the power rating of the fridge. (3 marks)
Question 15/18
(a) (i) State three uses of the electron gun in the cathode ray oscilloscope. (3 marks)
(ii) State the reason why the inner wall of a cathode ray oscilloscope tube is coated with graphite. (1 mark)
(iii) Describe how a cathode ray oscilloscope can be used to measure the voltage of a cell. (3 marks)
(b) Figure 5 shows an X-ray tube.
(i) On the figure, show with an arrow:
I. the direction of the electron beam in the tube; (1 mark)
II. The direction of the x-rays produced. (1 mark)
(ii) State two ways by which focusing of the electron beam is achieved in the tube. (2 marks)
Question 16/18
(a) (i) State the meaning of the term photoelectric emission. (1 mark)
(ii) Explain how the energy of a photon is used by the electrons during photoelectric emission. (2 marks)
(b) Explain the meaning of the term stopping voltage as used in the photoelectric effect. (2 marks)
(c) When a certain metal surface is illuminated with a light of wavelength 4.0 x 10⁻⁷ m, it emits photoelectrons whose kinetic energy is 6.6 x 10⁻²⁰ J. (Planck’s constant is h is 6.6 x 10⁻³⁴ Js and speed of light c is 3.0 x 10¹⁰ m/s) .)
Determine the:
(i) Energy of a photon of the incident light. (3 marks)
(ii) Work function of the metal surface. (3 marks)
Question 17/18
(a) Explain how visible tracks of radiation are formed in the expansion cloud chamber when the moist air in the chamber expands. (3 marks)
(b) The following equation shows a radioactive decay series.
(i) State the name of the radiation emitted. (1 mark)
(ii) State what would be observed on the leaf of a positively charged electroscope when the radiation identified in (i) passes close to the cap of the electroscope. (3 marks)
(c) A certain radioactive substance has a half–life of 8 hours. 10 g of the sample has an activity of 90 counts per minute. Determine the:
(i) Quantity of the sample that is active after 24 hours; (1 mark)
(ii) Activity of the remaining sample after 24 hours. (1 mark)
Question 18/18
(a) Use the energy band theory to explain why intrinsic semiconductors do not conduct at absolute zero temperature. (2 marks)
(b) Figure 6 shows a p – n junction diode connected to a source of e.m.f.
(i) State the type of biasing shown in the figure. (1 mark)
(ii) Explain what happens to the charge carriers at the junction. (3 marks)
(iii) In the space provided, sketch the current–voltage graph for the diode in the figure. (1 mark)
(c) Figure 7 shows a waveform generated by an alternating current source.
(i) On the axis provided, sketch the waveform obtained when a p – n junction diode is connected in series with the source.
(ii) Explain the shape of the waveform drawn in part (c)(i). (2 marks)
(d) Figure 8 shows diodes, resistors, and an ammeter connected to 6 V d.c. source.
Determine the ammeter reading when the switch S is closed. (3 marks)
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