CBSE · Class 12 · Science
Know the paper before you walk into the hall.
Marking schemes, paper pattern, passing rules, and a simple preparation roadmap — laid out plainly. Not a coaching brochure. Just the things that actually matter when the exam date gets close.
100marks
total per subject
3hrs
typical theory paper
33%
minimum passing mark
the last week before boards
Marking scheme
Paper pattern
Roadmap
know your numbers
How each subject adds up to 100.
Theory, practical and internal assessment don't all carry the same weight. Knowing the split tells you where to invest your time in the final weeks.
Chemistry
Total 100Mathematics
Total 100Biology
Total 100English Core
Total 100Optional 5th
Total 100
what to expect on the paper
Boards test more than memory.
Modern CBSE papers mix recall with application. Here are the four question types you'll see across most subjects.
Competency-based questions
You're given an unfamiliar situation and asked to apply what you learned. The rule is the same — the setting is new. Practice recognising which chapter a question is really testing.
Case & source-based
A short passage, data set or scenario is followed by 3–5 questions. Read the passage twice. Most marks are lost because students answer from memory instead of from what the passage actually says.
Short & long answers
Step marks matter. Write the formula first, then substitute, then answer. Even if the final number is wrong, a clear method earns partial credit. Diagrams where they're asked for.
Objective questions
MCQ, assertion-reason, fill-in-the-blank. This section is where students lose the most careless marks. Watch units, signs, negative options and "not" in the question stem.
in the exam hall
Three steps, every question.
01
Read
Read the whole question before you start writing. Identify what's given, what's asked, and what units are expected. A five-second pause saves five minutes of correction.
02
Solve
Formula first, substitution second, answer third. Keep work organised down the page. If you get stuck, move on — come back with fresh eyes.
03
Review
Reserve the last 10–15 minutes. Revisit unanswered questions, then check for missing units, wrong signs, and questions you may have misread.
Passing rules are not just one number.
A lot of students think "33% overall" is the only rule. That's usually wrong. In practical subjects you often need a minimum in theory and a minimum in practicals separately. Internal assessment is graded differently. Always check the current year's official CBSE documents.
33% overall benchmark
The standard minimum across most CBSE subjects — but not the only rule that applies.
Theory vs practical split
Physics, Chemistry and Biology often need a separate pass in each component.
Internal assessment
Projects, notebooks and school exams count. Keep them up to date during the year.
Official documents rule
CBSE circulars and the curriculum document are the final authority — not any website.
study roadmap
A preparation plan that actually fits a month.
Five stages, in order. Not a fixed timetable — just the right sequence, so you don't spend February re-reading chapter one.
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01
Build the concepts
Start with NCERT. Every definition, derivation, reaction and formula is on the table. Don't skip the derivations to save time — they come back as 3 and 5 mark questions.
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02
Work through exercises
Move from solved examples to unsolved exercises. Track which chapters keep tripping you up. Those are the ones that need a second pass, not the ones you already know.
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03
Previous-year papers
Do the last 5 years of board papers and the official CBSE sample paper. Not to memorise answers — to understand how questions are phrased and how marks are distributed.
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04
Full-length mocks, timed
Three hours, no interruptions, no phone. Then spend an hour analysing what went wrong — not just the score. The analysis is where the marks come from.
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05
Final revision
Formulas, definitions, diagrams, common mistakes, and the chapters you're least confident about. Nothing new. Just retrieval practice of what's already there.
common questions
Things students ask us most.
What is the actual passing mark for Class 12 Science?
For most CBSE subjects, you need a minimum of 33% overall. But for subjects with practicals — Physics, Chemistry, Biology — you also need a separate minimum in the theory paper and in the practical. So a student can theoretically score 40% overall and still fail if they score too low on one component.
Always confirm the exact rule for your exam year from the official CBSE curriculum document — not from any website, including this one.
How much time should I give each subject?
There's no universal answer, but a reasonable starting point for the final month is: equal time for your three weakest subjects, and about half that for your two strongest. The point is to close gaps, not to reward subjects you already enjoy studying.
Are previous-year questions really that important?
Yes, but not for the reason most students think. The value is not in seeing the same question again — it's in understanding the language and structure the examiner uses. Once you notice how a 3-mark question is phrased differently from a 5-mark one, you write better answers immediately.
Is it too late to start if I'm behind?
Not if you're reading this before the exam. The biggest mistake students make when they're behind is trying to cover everything equally. Instead, focus on the high-weightage chapters first, then the ones you can pick up quickly. Two chapters done well are worth more than six chapters done badly.
Do I need to write the whole derivation for full marks?
Generally, yes — the steps are the marks. Examiners award marks for the method, not just the final expression. Even if you don't remember the last line, showing the setup and half the algebra usually earns more than a blank response.
Is Shorveer Notes an official CBSE resource?
No. Shorveer Notes is an independent study resource. We are not affiliated with CBSE, NCERT, or any school or board. Every number, rule and date on this page is for general guidance only and should always be verified against the official CBSE documents for your examination year.
Disclaimer Please read this before relying on any information on this page.
Not an official CBSE resource
Shorveer Notes is an independent study guide. It is not affiliated with, endorsed by, or connected to CBSE, NCERT, or any school or board. This page is educational guidance only.
Marks can change between years
The marking schemes shown here reflect the typical structure of recent exam cycles. CBSE can and does adjust theory/practical weightings. Always confirm current numbers in the official curriculum document for your exam year.
Passing rules vary by subject
The "33%" rule is general guidance, not universal. Subjects with practicals often apply a separate minimum in theory and practical. Check the exact rule for each subject before drawing conclusions.
Dates, syllabus and patterns change
Exam dates, sample papers, syllabus revisions and question paper design are released by CBSE on their official channels. This site does not publish those announcements and cannot guarantee they are reflected here in real time.
No guarantee of accuracy
While every effort is made to keep the information current, no guarantee is made that this page is error-free, complete, or up to date at the moment you read it. If you spot something wrong, please report it.
No liability for outcomes
Shorveer Notes accepts no responsibility or liability for any academic outcome — including marks, grades, eligibility decisions or exam results — arising from reliance on the information presented here.
Not professional advice
Nothing here constitutes academic, career, legal or professional advice. For decisions about subject choices, board registration, exam eligibility or career paths, consult your school, teachers or a qualified advisor.
Copyright and trademarks
"CBSE", "NCERT" and related marks belong to their respective owners and are used here only for descriptive and identification purposes. No claim of ownership is made.
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