Assertion and Reason Practice Questions

5 questions per page • Detailed step-by-step solutions

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Question 21
Medium
Atmospheric pressure decreases exponentially with increasing altitude above sea level.|Atmospheric pressure at mean sea level is about 101.3 kPa.
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.
E Both (A) and (R) are false.
Correct Answer: B

Explanation:

Assertion (A) is true; the Barometric equation shows P(h) = P₀ e^(-Mgh/RT). Reason (R) is true; standard sea-level pressure is 101.325 kPa (1013.25 hPa). A sea-level value does not explain how pressure falls with height; the exponential decay comes from air being compressible, so option B.
Question 22
Easy
The speed of electromagnetic waves in a vacuum is independent of the frequency or wavelength of the radiation.|Electromagnetic waves are transverse, with electric and magnetic fields perpendicular to each other and to the direction of travel.
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.
E Both (A) and (R) are false.
Correct Answer: B

Explanation:

Assertion (A) is true; radio waves, gamma rays, and visible light all travel at the exact same speed in free space. Reason (R) is true; E, B and the propagation direction form a mutually perpendicular set. Transverse geometry does not explain frequency-independent speed, which follows from c = 1/√(μ₀ε₀); option B.
Question 23
Medium
A hollow metal sphere charged with positive electricity exhibits maximum electric potential at its center, which gradually decreases toward its surface.|The electric field inside a charged conducting shell is strictly zero everywhere, meaning no work is done moving a charge within the interior.
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.
E Both (A) and (R) are false.
Correct Answer: D

Explanation:

Assertion (A) is false; potential does NOT decrease from center to surface; it is uniform and constant throughout the entire interior, exactly equal to the potential at the surface (V_inside = V_surface = q / 4πε₀R). Reason (R) is true; since E = -dV/dr = 0 inside, dV = 0, proving potential is constant everywhere inside. With (A) false and (R) true, option D is correct.
Question 24
Medium
The Quit India Movement of August 1942 was characterized by immediate, widespread, and decentralized public uprisings across India.|The Quit India resolution was passed at the Gowalia Tank Maidan in Bombay, where Gandhi gave the call 'Do or Die'.
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.
E Both (A) and (R) are false.
Correct Answer: B

Explanation:

Assertion (A) is true; the movement rapidly transformed into a spontaneous, leaderless mass revolt with underground parallel governments (e.g., Ballia, Tamluk, Satara). Reason (R) is true; the AICC passed the resolution there on 8 August 1942. The venue and slogan do not explain the decentralised character; that came from the overnight arrest of the entire leadership, so option B.
Question 25
Medium
The Bardoli Satyagraha of 1928 was led by Vallabhbhai Patel against arbitrary land revenue assessment hikes imposed by the Bombay Presidency.|The successful resistance led the women of Bardoli to confer the honorary title 'Sardar' upon Vallabhbhai Patel.
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.
E Both (A) and (R) are false.
Correct Answer: B

Explanation:

Assertion (A) is true; Patel organized the 1928 no-tax peasant movement against a 22% unjust tax hike. Reason (R) is true; the triumph earned Patel the title 'Sardar' from the peasant women. While both statements are historically correct, the conferring of the honorific title in (R) is a consequence or tribute, NOT the explanatory cause of why Patel launched the movement against land revenue in (A); hence option B.
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