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EEJ MAIN Physics QUESTION #994
Question 1
Assertion (A): A simple pendulum taken to a planet with mass 4 times and radius 2 times that of Earth has the same time period. Reason (R): The mass of the pendulum remains unchanged on Earth and the planet.
  • (A) is false but (R) is true
  • (A) is true but (R) is false
  • Both (A) and (R) are true and (R) is the correct explanation of (A)
  • Both (A) and (R) are true but (R) is NOT the correct explanation of (A)✔️
Correct Answer Explanation
Planet's \(g' = \frac{GM'}{R'^2} = \frac{G\cdot4M}{(2R)^2} = \frac{4GM}{4R^2} = g\). So time period \(T=2\pi\sqrt{L/g}\) remains same — (A) is true. (R) is also true but the reason is equal \(g\), not unchanged mass. So (R) is not the correct explanation.