Chapter guides
JEE chapter wise questions, formulas and the mistakes that cost marks
Each guide takes one chapter and answers the same four questions: how many marks it is worth, which formulas you are expected to know cold, which mistakes cost students marks in it, and whether you can still solve its questions under time. BrainStride is an AI tutor for JEE, NEET and Olympiad preparation that runs a 20-minute diagnostic, maps your weak chapters and writes a daily plan, with every solution checked by teachers.
Free · no sign-up · quiz at the end of every guide
Updated September 2026
Chapter guides by exam and subject
10 guides
JEE Main · Maths
NEET UG · Physics
JEE Main · Chemistry
NEET UG · Biology
JEE Main · Physics
How should you use a chapter guide?
Not by reading it end to end. A chapter guide is a diagnostic tool: it tells you whether a chapter is finished, and the usual answer is "nearly, in the parts that are easy to revise".
Start from the chapters that are costing you marks, not the ones that are next. If you have not mapped that yet, the 20-minute diagnostic names the chapters where your marks leak, and the syllabus tracker shows which units you have not touched at all. Working through guides in syllabus order is the slowest way to use them.
Read the mistakes list before the formulas. Most chapters lose marks in four or five specific ways — a sign convention dropped, a condition not checked, an NCERT line half-remembered. If you recognise one of your own errors there, that is your next practice session, and the rest of the guide is revision you do not need today.
Finish with the quiz, under time. A chapter is done when you can answer its questions without looking anything up, not when you have read the theory again. If the quiz goes badly, the guide names what to fix rather than telling you to revise the whole chapter.
Which chapters have guides?
The guides cover the chapters that carry the most marks and cause the most trouble, across JEE Main and NEET UG — Physics, Chemistry, Mathematics and Biology. New guides are added chapter by chapter, so the list above grows.
For a subject-level view instead — every chapter in the syllabus with its weightage range and the mistake it usually catches — start from the subject pages: JEE Main Physics, JEE Main Chemistry, JEE Main Maths, NEET Physics, NEET Chemistry and NEET Biology.
How is the weightage in each guide worked out?
By counting questions in past papers ourselves. NTA does not publish chapter weightage for either exam, so every number in these guides is BrainStride's analysis of past papers, given as a range and labelled on the page. The JEE Main syllabus and NEET syllabus pages carry the official unit lists those counts are mapped to.
Chapter guides: common questions
Are BrainStride chapter guides free?
Yes. Every chapter guide is open without an account, including the formulas, the mistakes list, the solved examples and the quiz. An account is needed only for the 20-minute diagnostic, the weak-chapter map and a daily plan built from your own mistakes, and the Starter plan that includes all three is free forever.
Which chapters carry the most marks in JEE Main?
JEE Main gives every subject 25 questions and 100 marks, so no single chapter dominates. In our analysis of past papers, Calculus, Coordinate Geometry, Electrostatics and Current Electricity, Modern Physics and Organic Chemistry recur most often, usually two to seven questions each depending on the area. NTA publishes no official chapter weightage, so treat these as ranges for planning.
Which chapters carry the most marks in NEET?
Biology decides NEET: 90 of the 180 questions and 360 of the 720 marks. Within it, Genetics and evolution, Human physiology and Ecology account for the largest share in our analysis of recent papers. Physics and Chemistry carry 45 questions each, where Modern physics, Electrostatics, Chemical bonding and Organic basics recur most.
Do chapter guides include previous year questions?
Each guide shows how often the chapter has appeared in recent papers and works through solved examples in the style the exam actually uses, with the reasoning written out rather than just the answer. The counts come from our own analysis of past papers, and each guide names the years it covers.
How do I know when a chapter is actually finished?
When you can solve its previous-year questions under time without looking anything up, and the mistakes listed in its guide no longer describe you. Reading the theory again does not test either of those. Every guide ends with a short quiz for exactly this reason, and BrainStride brings cleared chapters back weeks later to check the knowledge held.
Find out which chapters are actually costing you marks.
Twenty minutes, twenty-five questions, and a weak-chapter map that tells you which guides to open first.