Choose the correct option for the following Assertion (A) and Reason (R).

Question

G1 Physics · Accepted Answer

For a sphere under Stokes drag, τ = m/(6πηr). Using m = (4πr³/3)ρₛ, we get τ = 2ρₛr²/(9η). For the same material and liquid, τ ∝ r². Therefore a smaller sphere has a smaller time constant and approaches its terminal speed more rapidly. Both Assertion and Reason are true, and the Reason correctly explains the Assertion. Correct option: A.