Physics is the subject where students most often say they understood the chapter and still cannot do the question. The cause is usually upstream: a topic the question depends on was never solid. This is the dependency chain behind HSC physics, written by topic rather than by chapter number so it does not break when an edition reorders things. Follow your own textbook's contents page for the exact chapter names.
The chains
Mechanics chain (mostly 1st paper)
- Measurement and vectors come first. Almost every later topic uses vector addition, components or units without saying so.
- Motion and Newtonian mechanics rest on vectors. Forces, momentum and projectile motion all need component-wise thinking.
- Work, energy and power rest on Newtonian mechanics. Gravitation and periodic motion lean on both.
- Waves rest on periodic motion — wavelength, frequency and phase are the same ideas as period and amplitude, applied to a medium.
Heat and gases chain
- Ideal gas and the kinetic theory of gases come before thermodynamics. The first law of thermodynamics is easy to memorise and hard to use if gas behaviour is shaky.
Electricity chain (mostly 2nd paper)
- Static electricity — charge, field, potential — comes before current electricity.
- Current electricity comes before the magnetic effects of current, and both come before electromagnetic induction and alternating current.
- Semiconductors and electronics lean on current electricity and a little atomic structure.
Light and modern physics chain
- Geometrical optics (rays, lenses, mirrors) is largely separate and mostly geometry.
- Physical optics — interference, diffraction, polarisation — rests on waves from the 1st paper. This is the topic where students who skipped waves stop understanding anything.
- Introductory modern physics and atomic and nuclear physics come near the end and lean on waves and electricity.
Find the break in ten minutes
Pick the topic that is going badly and walk one step up its chain. Can you explain the previous topic in three sentences without the book? If yes, go one more step up. The first topic you cannot explain is where to start, not the topic that felt hard. If physical optics is hard, test yourself on waves; if electromagnetic induction is hard, test current electricity and the magnetic effects first.
Rebuilding the broken topic
Name the topic to Porphy and answer its short intake about what you already know. It builds a course from the prerequisites up — a 3–4 part overview if you half-know it, a 5–7 part course if you skipped it. When a line stalls you, highlight it and have the tutor explain it out loud on the whiteboard, in Bangla with the technical terms left in English. Then generate an MCQ set from the same material; see how to make MCQs from a PDF or slides for how to check them.
পদার্থবিজ্ঞানে 'কঠিন chapter' বলে কিছু নেই — আছে একটা না-বোঝা আগের topic, যার ওপর পরের topic দাঁড়িয়ে আছে।
This is a map of how the ideas depend on each other, not a copy of the NCTB syllabus and not a prediction of what your board will ask. Porphy does not know your board's past questions or your teacher's emphasis — use your textbook and past papers alongside it.
For the weekly shape of the last stretch before the exam, see an 8-week HSC study routine, and for the method on any skipped chapter, HSC preparation with AI.
Every new account starts with 2,000 credits free — no card, no subscription, and they never expire. A full researched course runs about 600–1,200 credits, an MCQ set or flashcard deck 10–30, and the voice tutor 20–60 a minute. Free accounts run a lighter pipeline so the credits go further: at most 3 parts per course, with text and tables in place of generated visualizations.