Question

Assertion :If the radius of earth is decreased keeping its mass constant, effective value of $g$ may increase or decrease at pole. Reason: Value of $g$ on the surface of earth is given by $g=\frac{GM}{R^2}$

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is D Both Assertion and Reason are incorrect

By changing the radius, moment of inertia will change. Hence, angular speed $\omega$ will change.But ω has no effect on the value of g on pole.

The earth is not a perfect sphere. As the radius of the earth increases from the poles to the equator, the value of g becomes greater at the poles than at the equator.