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Updated 1 November 2026. These KCSE Physics Paper 3 questions and answers are original practical tasks in the 232/3 style, each with a set of sample readings and a fully worked analysis: table, graph, gradient and final calculation. The 2026 Physics practical is the last KCSE paper, on Friday 20 November, 8.00 to 10.30 am, according to the KNEC 2026 KCSE Examination Timetable. These are revision tasks, not KNEC papers or a KNEC marking scheme.
How Physics Paper 3 Is Set and Marked
Physics Paper 3 is a 2 hour 30 minute practical. Recent papers have usually had two questions and a total of 40 marks, and the cover page normally asks you to spend the first 15 minutes reading the whole paper and checking your apparatus. Always follow the instructions on your own paper on the day. Marks come from four places:
- Setting up and following the procedure correctly.
- Readings recorded in a table with units and consistent decimal places.
- A graph with labelled axes, a sensible scale, correctly plotted points and a line of best fit.
- Calculations from the graph, usually a gradient or intercept, with units.
The calculator rules in the KNEC timetable apply: Physics is on the list of subjects where a non-programmable calculator without a cover may be used. Phones in the exam centre lead to cancelled results.
The practical is where boys and girls are evenly matched: Physics was one of seven subjects in which male and female candidates performed comparably in the 2025 KCSE, according to the Citizen Digital 2025 KCSE performance report. Careful technique, not talent, decides most of these 40 marks.
What Is the KCSE Physics Paper 3 Confidential?
Many students search for the “Physics Paper 3 confidential”. It is the list of apparatus and preparation instructions that KNEC sends to schools ahead of the practical so the laboratory can be set up. It is a restricted document for the school, not a copy of the questions, and anything sold online as the 2026 confidential with answers should be treated as a scam. The useful lesson is that the apparatus is standard: metre rules, springs, pendulum bobs, glass blocks, lenses, cells, voltmeters, ammeters and resistance wire. Practise with all of them.
KCSE Physics Paper 3 Questions and Answers (Original Practice)
Task 1: Simple pendulum (20 marks)
Set up a pendulum and time 20 oscillations for lengths L = 0.30, 0.40, 0.50, 0.60, 0.70 and 0.80 m. Find the period T and T². Plot T² (y-axis) against L and use the gradient to find g, given T² = (4π²/g)L.
| L (m) | Time for 20 (s) | T (s) | T² (s²) |
|---|---|---|---|
| 0.30 | 22.0 | 1.10 | 1.21 |
| 0.40 | 25.4 | 1.27 | 1.61 |
| 0.50 | 28.4 | 1.42 | 2.02 |
| 0.60 | 31.0 | 1.55 | 2.40 |
| 0.70 | 33.6 | 1.68 | 2.82 |
| 0.80 | 35.8 | 1.79 | 3.20 |
Worked answer: T = time ÷ 20. The graph is a straight line through the origin. Using two points far apart on the line, (0.30, 1.21) and (0.80, 3.20): gradient = (3.20 − 1.21) ÷ (0.80 − 0.30) = 1.99 ÷ 0.50 = 3.98 s²/m. Then g = 4π² ÷ gradient = 39.48 ÷ 3.98 ≈ 9.9 m/s². Marks go to the table (T and T² to consistent decimal places), axes labelled with units, at least five points plotted correctly, the gradient shown with a large triangle, and g with its unit.
Task 2: Resistance of a wire (20 marks)
Connect a cell, switch, ammeter and a length of resistance wire, with a voltmeter across the wire. Record V and I for lengths of 20, 40, 60, 80 and 100 cm, find R = V/I for each, and plot R against length l.
| l (cm) | V (V) | I (A) | R (Ω) |
|---|---|---|---|
| 20 | 0.40 | 0.50 | 0.80 |
| 40 | 0.70 | 0.44 | 1.59 |
| 60 | 0.90 | 0.38 | 2.37 |
| 80 | 1.05 | 0.33 | 3.18 |
| 100 | 1.16 | 0.29 | 4.00 |
Worked answer: R rises in proportion to length, so the graph is a straight line through or near the origin. Gradient = (4.00 − 0.80) ÷ (100 − 20) = 3.20 ÷ 80 = 0.040 Ω/cm, which is the resistance per centimetre (4.0 Ω/m). If the question gives the cross-sectional area A, resistivity ρ = gradient × A, in Ω m once units are converted. Common errors: reading the ammeter on the wrong scale and forgetting to open the switch between readings, which heats the wire and changes R.
Short items that often accompany a task
Why time 20 oscillations instead of one? To reduce the error from reaction time when starting and stopping the stopwatch. Why open the switch between readings? To stop the wire heating up, which would increase its resistance. State one precaution when using a glass block. Place the pins far apart and view their bases, not their heads, to reduce error in locating the ray.
Where Practical Marks Are Lost
- Inconsistent decimal places in one column, such as 1.1, 1.27 and 1.420.
- A small graph that uses less than half the grid.
- Gradients worked out from table values instead of points on the line.
- Answers given without units, or g quoted to six significant figures.
More Physics Revision
For the experiments that keep returning, read KCSE Physics practical Paper 3 preparation. Test theory in the Physics Paper 3 challenge and the KCSE Physics quiz, and practise Paper 1 with KCSE 2025 Physics Paper 1 questions and answers or the Physics Paper 1 revision guide. All physics papers are on KCSE Physics practice papers; every subject is on the KCSE hub and the KCSE quiz list.
Frequently Asked Questions
How long is KCSE Physics Paper 3?
2 hours 30 minutes on the KNEC 2026 timetable, usually with two practical questions worth 40 marks in total.
What is the Physics Paper 3 confidential?
It is KNEC’s restricted apparatus and preparation list for schools, not the question paper. Copies sold online with answers are scams.
Do you have the KCSE Physics Paper 3 marking scheme?
No. These are original practical tasks with sample readings and worked analysis, not KNEC material.
When is the Physics practical in 2026?
Friday 20 November 2026, 8.00 am to 10.30 am, the last paper of the 2026 KCSE.
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