SPM Physics 2026: Form 4 takes the biggest bite

Lots of students revise Physics in textbook order: Chapter 1, Chapter 2, Chapter 3… and run out of time before they reach Form 5. We wanted to know whether that order makes sense, so we counted.

We took 13 Physics trial papers from 2026 (11 states, plus MRSM and school papers) and matched every one of the 520 Paper 1 questions to its KSSM chapter and subtopic.

In short: three Form 4 chapters dominate the paper, and the first chapter in the book (Measurement) is the one that comes up least.

The short answer

• 5 chapters cover 55% of the questions: Force and Motion I, Waves, Light and Optics (all Form 4), Pressure (Form 5) and Heat (Form 4).
• Force and Motion I is the biggest: 13.5% of questions, about 5 per paper.
• The top three Form 4 chapters alone are 36%: Force and Motion I, Waves, and Light and Optics. That's roughly 14 of the 40 questions.
• Measurement (F4 Ch. 1) comes up least: 2.9%, about one question per paper.
• Five subtopics appear in 9 papers out of 10: Refraction of Light, Archimedes' Principle, the Gas Laws, Transistors and Nuclear Energy.

If you don't have much time left

A week left? Start with Force and Motion I, Waves, and Light and Optics. Those three are close to a third of Paper 1. Then do Pressure and Heat.

Three days left? Nail the five "9 in 10" subtopics below. Each is usually one short calculation, so learn the formula and work through two or three examples.

The night before? Run through your formula list with the units. In Physics a lot of marks go on units (°C versus K, cm versus m), not on the concept.

Every chapter, ranked (2026 trial papers)

"Qs/paper" is the average number of questions from that chapter in one 40-question paper.

Form 5 chapters are more even, mostly 2 to 3 questions per paper each, so don't drop Form 5. It's just that when time is really short, Form 4 pays back faster.

Subtopics that turn up in almost every paper

The count below is how many papers (out of every 10) had at least one question from that subtopic.

• F4 6.1 Refraction of Light · 9 in 10 papers. n = sin i / sin r, and n = real depth / apparent depth. The question usually gives you two of the three values.
• F5 2.5 Archimedes' Principle · 9 in 10 papers. Buoyant force = weight of fluid displaced. An object floats when the buoyant force equals its weight.
• F4 4.4 Gas Laws · 9 in 10 papers. Boyle's, Charles's and Gay-Lussac's laws. 1.4 questions per paper on average, and temperature must be in kelvin.
• F5 5.3 Transistor · 9 in 10 papers. The transistor as a switch: a small base current turns on a large collector current. Often paired with a light-dependent resistor (LDR) or a thermistor.
• F5 6.2 Nuclear Energy · 9 in 10 papers. E = mc², with the mass defect in kg. 1 u = 1.66 × 10⁻²⁷ kg.
• F4 2.7 Impulse and Impulsive Force · 8 in 10 papers. Impulse = Ft = mv − mu. A longer impact time means a smaller impulsive force (airbags, crash mats).
• F4 5.6 Interference of Waves · 8 in 10 papers. x = λD / a. Be able to pick out constructive and destructive points on a diagram.
• F4 6.2 Total Internal Reflection · 8 in 10 papers. sin c = 1/n. Only happens when light goes from a denser to a less dense medium and the angle of incidence is above the critical angle.
• F5 3.2 Resistance · 8 in 10 papers. R = ρl / A. A longer or thinner wire has a higher resistance.
• F5 4.2 Electromagnetic Induction · 8 in 10 papers. Faraday's law (how fast the flux changes) and Lenz's law (the induced current opposes the change).

Mistakes we keep seeing

1. Celsius in the gas laws. Convert to kelvin (add 273) before it goes into the formula. This is the single most common slip in Gas Law questions.
2. Signs in the lens formula. For a concave lens f is negative, and a virtual image gives a negative v.
3. Faraday versus Lenz. How fast the magnet moves changes the size of the induced current (Faraday). The direction comes from Lenz.
4. Speed-time graphs. Area under the graph = displacement, gradient = acceleration. Plenty of students mix this up with displacement-time graphs.
5. cm and m. Wavelengths and distances in interference questions are often given in cm or mm. Convert first.

How we counted, and what it can't tell you

The data comes from 13 Physics Paper 1 trial papers from 2026 (state, MRSM and school papers) in Cerdek's question bank: 520 objective questions in all. Each question was matched to a subtopic of the KSSM Form 4 and 5 Physics textbooks. A question touching two subtopics counts as half for each.

The limits:

• These are trial papers, not real SPM papers. They follow the SPM format, but this isn't a prediction of the questions.
• Paper 1 (objective) only.
• With 13 papers, a small gap (under 1%) between two chapters means nothing.

You can see the same analysis, by year and by form, in the Topic Insights feature of the Cerdek app.

Frequently asked questions

Which Physics chapter came up most in the 2026 SPM trial papers?

Force and Motion I (Form 4, Chapter 2), with 13.5% of questions, about 5 per Paper 1. Next were Waves (11.7%) and Light and Optics (11.0%), both Form 4. This is based on 520 questions from 13 trial papers of 2026.

Does Form 4 or Form 5 Physics come up more?

Form 4, slightly: 53% of questions against 47% for Form 5. But three Form 4 chapters (Force and Motion I, Waves, and Light and Optics) are already 36% on their own.

Which Physics subtopics are almost certain to come up?

Refraction of Light, Archimedes' Principle, the Gas Laws, Transistors and Nuclear Energy each appeared in 9 out of 10 trial papers of 2026.

Can I skip the Measurement chapter?

It comes up least (2.9%, about one question per paper), but reading instruments and errors are skills used in other chapters. Revise it quickly rather than dropping it.