MCQ
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : A simple pendulum is taken to a planet of mass and radius, 4 times and 2 times, respectively, than the Earth. The time period of the pendulum remains same on earth and the planet.
Reason (R) : The mass of the pendulum remains unchanged at Earth and the other planet. In the light of the above statements, choose the correct answer from the options given below :
  • Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
  • B
    (A) is true but (R) is false
  • C
    (A) is false but (R) is true
  • D
    Both (A) and (R) are true and (R) is the correct explanation of (A)

Answer

Correct option: A.
Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
(A) Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
Sol. $g =\frac{ GM }{ R ^2}$
$g^{\prime}=\frac{G(4 M)}{(2 R)^2}=g$
A is correct, R is correct ; but since $T =2 \pi \sqrt{\frac{\ell}{g}}$
doesn't depend on mass ; R doesn't explain A .

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