Assertion-Reason questions don't go away after Class 10 — they get harder, because the "reason" half now has to be technically precise, not just plausible-sounding. A Class 12 examiner can make an assertion true and a reason true and still fail you for missing that the reason doesn't actually cause the assertion. Here's exactly how the format works, with real worked examples across three streams.
Every assertion-reason question in a CBSE paper offers the same four choices:
Assertion: A metal comb does not retain charge when rubbed with hair, but a plastic comb does.
Reason: Metals are conductors and charges leak through the human body to the ground, while plastics are insulators and charges remain localized on the surface.
Answer: (A). Both statements are true, and the reason is exactly why — conductivity determines whether charge can escape through your hand to the ground. Insulators block that path, so the charge stays put.
Assertion: According to the Indian Partnership Act 1932, when a partnership deed is silent on interest on capital, no interest is payable to partners.
Reason: This provision applies because the Act treats interest on capital as an expense that must be explicitly agreed upon by all partners.
Answer: (B). The assertion is correct — no deed, no interest. But the reason mischaracterises why: it's not that interest is an "expense requiring agreement," it's that the Act simply grants no automatic entitlement to interest without one. Both statements are true in isolation; the reason just isn't the actual legal basis for the assertion.
Assertion: A 3-sector model is sometimes preferred to a single representative-good model because different sectors have different production conditions and technologies.
Reason: Agricultural and industrial commodities are produced under identical conditions, so sectoral aggregation is always preferred for precision.
Answer: (C). The assertion is true — the textbook explicitly justifies sectoral analysis on the grounds that production conditions differ. The reason is false: it claims those conditions are "identical," which directly contradicts the reasoning it's supposed to support.
Assertion: The Harappan Civilisation developed exclusively from Mesopotamian influences introduced through trade.
Reason: Archaeological evidence shows that Early Harappan cultures, dating to around 7000 BCE, emerged from local farming communities before the Mature Harappan phase.
Answer: (D). The assertion is false — the Mature Harappan phase grew out of local Early Harappan development, not exclusively external contact, even though trade with Mesopotamia did happen. The reason is true on its own and is, in fact, the evidence that disproves the assertion.
In Class 12 specifically, watch for reasons that sound like the right topic but get a mechanism backwards — like claiming production conditions are "identical" while arguing for why they should be treated separately. That's the exact trap examiners build into Type C.
Assertion-Reason practice for every Class 12 chapter
Science, Commerce, Humanities — all NCERT-grounded, 15 per chapter
Open Class 12 Physics →More on the same chapters: Class 12 Accountancy — Partnership Basic Concepts, Class 12 History — The Harappan Civilisation, or browse every Class 12 chapter. See also the full Class 12 chapter-wise notes and MCQs breakdown.