Last reviewed: 1 November 2026
Updated 1 November 2026. This page gives KCSE 2025 Physics Paper 1 questions and answers in the sense most students mean: original practice questions in the same format as the 2025 Physics Paper 1 (232/1), with worked answers that show formula, substitution and units the way examiners award marks. They are not the KNEC paper and not a KNEC marking scheme. The 2026 Physics Paper 1 is on Monday 16 November, 2.00 to 4.00 pm, on the KNEC 2026 KCSE Examination Timetable.
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The 232/1 Format
Physics Paper 1 lasts 2 hours and is marked out of 80. Section A has short questions worth about 25 marks; Section B has longer structured questions worth about 55 marks. All questions are compulsory. A non-programmable calculator and KNEC mathematical tables are allowed. Paper 1 is mainly mechanics, properties of matter and heat; waves, electricity, magnetism and modern physics dominate Paper 2 (232/2) on Wednesday 18 November.
In the 2025 KCSE, Physics was one of seven subjects in which male and female candidates performed comparably, according to the Education Cabinet Secretary’s results statement as reported in the Citizen Digital 2025 KCSE performance report.
KCSE 2025 Physics Paper 1 Questions and Answers: Section A Practice
1. A micrometer screw gauge with zero error of −0.02 mm reads 5.47 mm. Find the actual diameter. (2 marks)
Answer: Actual reading = reading − (zero error) = 5.47 − (−0.02) = 5.49 mm.
2. Explain why a dam wall is thicker at the bottom than at the top. (2 marks)
Answer: Pressure in a liquid increases with depth (P = ρgh), so the wall must be strongest at the bottom where the pressure is greatest.
3. A spring extends by 4 cm under a load of 20 N. Find the extension under 35 N, assuming the elastic limit is not exceeded. (2 marks)
Answer: Spring constant k = 20 ÷ 4 = 5 N/cm; extension = 35 ÷ 5 = 7 cm.
4. State why a thick glass tumbler is more likely to crack than a thin one when hot water is poured in. (2 marks)
Answer: Glass is a poor conductor; the inner surface expands faster than the outer surface, setting up unequal expansion and strain that cracks the glass. Thin glass heats more evenly.
5. A force of 40 N acts on an area of 0.02 m². Calculate the pressure. (2 marks)
Answer: P = F ÷ A = 40 ÷ 0.02 = 2,000 Pa (N/m²).
Section B Practice With Worked Answers
6. Linear motion (12 marks)
A car starts from rest and accelerates uniformly at 2 m/s² for 10 s, travels at constant velocity for 20 s, then decelerates uniformly to rest in 5 s. (a) Find the maximum velocity. (2) (b) Sketch the velocity-time graph. (3) (c) Calculate the total distance travelled. (4) (d) Find the deceleration. (3)
Worked answer: (a) v = u + at = 0 + 2 × 10 = 20 m/s. (b) A straight line from (0, 0) up to (10, 20), a horizontal line to (30, 20), then a straight line down to (35, 0), with labelled axes and units. (c) Distance = area under the graph = ½ × 10 × 20 + 20 × 20 + ½ × 5 × 20 = 100 + 400 + 50 = 550 m. (d) a = (0 − 20) ÷ 5 = −4 m/s², so a deceleration of 4 m/s².
7. Machines (10 marks)
A pulley system with a velocity ratio of 4 lifts a load of 600 N using an effort of 200 N. (a) Calculate the mechanical advantage. (2) (b) Calculate the efficiency. (3) (c) Give two reasons why efficiency is less than 100%. (2) (d) If the load rises 2 m, find the work done by the effort. (3)
Worked answer: (a) MA = load ÷ effort = 600 ÷ 200 = 3. (b) Efficiency = MA ÷ VR × 100% = 3 ÷ 4 × 100% = 75%. (c) Friction in the pulley bearings; work done lifting the movable pulley block and the string. (d) Effort distance = VR × load distance = 8 m; work = 200 × 8 = 1,600 J.
8. Quantity of heat (10 marks)
An electric heater rated 500 W heats 2 kg of water from 20 °C to 80 °C. (Specific heat capacity of water 4,200 J kg⁻¹ K⁻¹) (a) Calculate the heat absorbed. (3) (b) Find the time taken, assuming no heat loss. (3) (c) Explain why the actual time is longer. (2) (d) Define specific latent heat of vaporisation. (2)
Worked answer: (a) Q = mcΔθ = 2 × 4,200 × 60 = 504,000 J. (b) t = Q ÷ P = 504,000 ÷ 500 = 1,008 s (16.8 minutes). (c) Some heat is lost to the surroundings and absorbed by the container. (d) The quantity of heat needed to change a unit mass of a liquid at its boiling point to vapour without a change in temperature.
How Physics Paper 1 Marks Are Won
- Write the formula first, then substitute, then the answer with the unit. Many marking points sit on the substitution line.
- Convert to SI units before substituting: cm to m, g to kg, minutes to seconds.
- Draw graphs with a ruler, labelled axes and a scale that uses more than half the grid.
- Definitions must be exact. Learn them word for word.
Likely Topics for Physics Paper 1 in 2026
Teachers’ prediction lists for 232/1 usually include linear motion graphs, Newton’s laws and momentum, machines, gas laws, fluid flow, and heat transfer. Use them as a revision checklist; the real paper can test any topic in the syllabus.
Next Steps for Physics
Use the KCSE Physics Paper 1 revision guide for topic notes, then the Physics Paper 1 challenge and the KCSE Physics quiz for timed drills. More questions are on the Physics Paper 1 practice papers page, and the practical is covered in KCSE Physics Paper 3 questions and answers. Browse every subject from the KCSE hub or the KCSE quiz list.
Frequently Asked Questions
How many marks is KCSE Physics Paper 1?
80 marks: about 25 in Section A and about 55 in Section B, all compulsory, in 2 hours.
Is this the KCSE 2025 Physics Paper 1 marking scheme?
No. These are original practice questions in the 2025 format with worked answers, not KNEC material.
When is Physics Paper 1 in KCSE 2026?
Monday 16 November 2026, 2.00 pm to 4.00 pm.
Can I use a calculator in Physics Paper 1?
Yes, a non-programmable calculator without a cover, as listed in the KNEC timetable instructions.
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