Q 11-07-066JEE MainJEE Main 2024 (27 Jan, Shift 1)Easy
The acceleration due to gravity on the surface of earth is $g$. If the diameter of earth reduces to half of its original value and mass remains constant, then acceleration due to gravity on the surface of earth would be:
Answer: (D) $4g$
$g = \dfrac{GM}{R^2}$. With $M$ fixed and $R \to R/2$:
$$g' = \frac{GM}{(R/2)^2} = 4\,\frac{GM}{R^2} = 4g$$
Solution by Sreeraj P, M.Sc Physics