How many questions do the three modules account for in total?
When you prepare for CSCA Physics, thermodynamics, optics and modern physics often leave you hesitating: the exam tests so little of them, so is it really worth studying them? Here is an answer from three angles: the share of questions, the scope of the syllabus, and how to plan your review.
The official CSCA Physics Examination Syllabus (2025 Edition) lists five modules: Mechanics, Electromagnetism, Thermodynamics, Optics and Modern Physics. We counted 4 past papers (2025-12-21, 2026-01-25, 2026-03-15, 2026-04-25), 188 questions in total (4 questions missing).
- Thermodynamics: 7 questions (2, 2, 2 and 1 across the four papers), about 4%
- Optics: 8 questions (2 in each paper), about 4%
- Modern physics: 0 questions, not tested in any of the 4 papers and not tested in the official sample paper either
- The three modules together: 15 questions, about 8%
What the syllabus covers
Thermodynamics
- Kinetic theory of gases
- Ideal gas equation of state
- First law of thermodynamics
Optics
- Geometrical optics: law of reflection, law of refraction
- Physical optics: interference, diffraction
Modern physics
- Photoelectric effect
- Atomic structure
- Fundamentals of nuclear physics
So should you study them or not?
- Thermodynamics and optics reliably account for 1 to 2 questions in every paper, and they involve few concepts and formulas, so a small amount of time is enough to secure them. They are worth studying.
- Modern physics was not tested in any of the 4 papers, so if time is tight you can leave it until last; but it is, after all, written into the syllabus, so at the very least go through the definitions once.
- CSCA.PRO's physics mock exams set questions in this proportion: 2 on thermodynamics and 2 on optics. Modern physics does not appear in the mock exams and shows up only in the knowledge-point lessons and practice.
Formulas you must master
You must know the following formulas:
- Ideal gas equation of state: pV = nRT
- First law of thermodynamics: ΔU = W + Q (W is the work done on the gas by the surroundings, Q is the heat absorbed by the gas)
- Law of reflection: the angle of reflection equals the angle of incidence
- Law of refraction: n = sin i / sin r
- Photoelectric effect: Eₖ = hν − W₀
Next step
Start with the 15-minute diagnostic to see how well you have mastered each module, then go to the knowledge-point lessons to fill the gaps.