Assertion and Reason Questions and Answers

Answer: A

Correct answer: Both A and R are true and R is the correct explanation of A.

Air temperature falls by roughly \( 6.5^{\circ}\mathrm{C} \) for every kilometre of altitude, because the air aloft is thinner and further from the ground that warms it. That fall is precisely why mountains feel colder than the plains below. Both are true and R explains A.

Answer: C

Correct answer: A is true but R is false.

Weeds must indeed be kept out of a crop, so A is true. But the reason given is not the real one: weeds do their damage by competing for water, nutrients and light, and by harbouring pests - not merely by occupying space. R is false.

Answer: C

Correct answer: A is true but R is false.

Razia Sultan was the daughter of Iltutmish and succeeded him in 1236, so A is true. Iltutmish was no rebel: he was a slave-general of Qutb-ud-din Aibak who succeeded him lawfully and consolidated the Delhi Sultanate. R is false.

Answer: B

Correct answer: Both A and R are true but R is NOT the correct explanation of A.

Both statements are true - the Constitution came into force on 26 January 1950, and that day is kept as Republic Day. But R is a consequence of A rather than its cause; the date was chosen to commemorate the Purna Swaraj declaration of 1930. R does not explain A.

Answer: A

Correct answer: Both A and R are true and R is the correct explanation of A.

Muhammad-bin-Tughluq’s schemes - the token currency, the transfer of the capital to Daulatabad, the Deccan campaigns - were imaginative in conception and disastrous in execution. That combination is exactly what earned him the name. Both are true and R explains A.

Answer: C

Correct answer: A is true but R is false.

Shivaji did perfect guerrilla warfare, the ganimi kava of hit-and-run raids from hill forts, so A is true. But he adopted it because his forces were small and the terrain suited it, not out of fear - he attacked the Mughals repeatedly. R is false.

Answer: C

Correct answer: A is true but R is false.

Silver is not used for ordinary wiring, so A is true. But the reason is its cost, not its conductivity: silver is in fact the best conductor of electricity of all metals, which is why copper, the next best and far cheaper, is used instead. R is false.

Answer: A

Correct answer: Both A and R are true and R is the correct explanation of A.

The appendix is a vestigial remnant of the caecum, which in herbivores digests cellulose. In humans it takes no part in digestion, and its removal has no effect on it - which is exactly what makes it vestigial. Both are true and R explains A.

Answer: D

Correct answer: A is true but R is false.

Indian women do outlive Indian men - life expectancy at birth is around three years higher for females - so A is true. But the cause is not diet: nutritional discrimination generally runs the other way, and the advantage is largely biological. R is false.

Answer: A

Correct answer: Both A and R are true and R is the correct explanation of A.

Watt’s steam engine was developed for one industrial problem above all: pumping water out of flooded mines, work that the earlier atmospheric engines did wastefully. His separate condenser cut the fuel needed by three-quarters and made the engine practical. Both are true and R explains A.