Assertion-Reason questions are MCQs with a twist: you are not just picking a true fact, you are judging two statements and the relationship between them. Students who know the chapter still lose marks because they skip that middle step.
Solve Assertion-Reason questions in three steps: decide whether the Assertion (A) is true, decide whether the Reason (R) is true, then, only if both are true, decide whether R actually explains A. Match the result to the four standard options.
What are Assertion-Reason questions?
An Assertion-Reason question gives two statements: an Assertion (A), which is a claim, and a Reason (R), which is offered as its explanation. You choose from four fixed options describing whether each is true and whether R explains A. In the Class 10 Science paper they are a small number of one-mark MCQs in the objective section (check the current sample paper for the exact count), but they are notorious for catching students who otherwise know the content.
What do the four options mean?
The wording is standard across CBSE papers:
| Option | Meaning |
|---|---|
| (a) | Both A and R are true, and R is the correct explanation of A. |
| (b) | Both A and R are true, but R is not the correct explanation of A. |
| (c) | A is true, but R is false. |
| (d) | A is false, but R is true. |
(Some papers also include a "both false" case; always read the options as printed.)
How do you solve an Assertion-Reason question?
Step 1: Judge the Assertion on its own
Ignore the Reason completely. Is the claim true? Do not let a convincing Reason bend your judgement.
Step 2: Judge the Reason on its own
Now ignore the Assertion. Is this statement true as a general fact from the syllabus?
Step 3: If both are true, test the link
Only now ask: does R explain why A is true? "Because" is the test. Say "A is true because R". If the sentence makes sense causally, choose (a). If both are true but the sentence is a non sequitur, choose (b).
Can you see a worked example?
Here is an original example, written for teaching (not taken from any exam):
Assertion: A concave mirror can form a real image. Reason: A concave mirror can converge a parallel beam of light.
Step 1: A is true (a concave mirror forms real images when the object is beyond the focus). Step 2: R is true (parallel rays converge at the focus). Step 3: is A true because R? Converging light is what allows rays to meet and form a real image, so yes: option (a).
Now change the Reason to "A concave mirror has a curved surface." R is true, but it does not explain A (a convex mirror is also curved and cannot form a real image of a real object). Both true, R not the explanation: option (b).
What are the common Assertion-Reason mistakes?
- Merging the two statements. Judge them separately first.
- Choosing (a) whenever both look true. Two true statements are not automatically linked.
- Trusting the Reason because it sounds textbook-like. A Reason can be a true statement that explains nothing, or a subtly false one.
- Missing small qualifiers such as "always", "only" and "all", which can make an otherwise correct statement false.
- Never practising the format. It is a skill separate from knowing the chapter. See also common Science MCQ mistakes.
What is a good Assertion-Reason practice strategy?
- Learn the four options by heart so you never waste time decoding them.
- Practise with the three steps written out for your first twenty or so questions, then do them mentally.
- After each question, write one line on why A and R are true or false, and whether the link holds.
- Sort your misses into "judged a statement wrong" (concept gap) and "judged the link wrong" (logic gap). Revise accordingly.
- Practise across chapters. Chemistry Assertion-Reason questions often hinge on reactivity or bonding; Physics on laws and formulas; Biology on processes and causes.
- Revisit misses after a few days. This is the same spaced-repetition idea covered in active practice vs passive reading.
How does MindVsYou help with Assertion-Reason practice?
Assertion-Reason questions appear as part of the board MCQs you practise on MindVsYou. Each is marked instantly with an explanation, which shows you exactly which statement or which link you misjudged. Your accuracy is tracked by chapter, and missed MCQs come back through revise-wrong-answers, so you can re-test yourself after a gap. Start with the Science MCQ practice guide.
Frequently asked questions
What is an Assertion-Reason question?
It is an MCQ with two statements, an Assertion and a Reason. You decide whether each is true and, if both are true, whether the Reason correctly explains the Assertion.
How many Assertion-Reason questions come in the Class 10 Science paper?
A small number of one-mark questions in the objective section. The exact count can vary, so check the current-year CBSE sample paper.
If both statements are true, is the answer always (a)?
No. Choose (a) only if the Reason correctly explains the Assertion. If both are true but unrelated, the answer is (b).
How can I get better at Assertion-Reason questions?
Judge each statement separately, then test the link with the word because. Practise the format regularly and review why you missed each one.
Practise board MCQs, including Assertion-Reason
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