Q 11-07-132JEE MainJEE Main 2022 (28 Jul, Shift 1)Easy
If the radius of earth shrinks by $2\%$ while its mass remains same. The acceleration due to gravity on the earth's surface will approximately
Answer: (D) increase by $4\%$
$g = \dfrac{GM}{R^2}$, so for small changes
$$\frac{\Delta g}{g} = -2\frac{\Delta R}{R} = -2(-2\%) = +4\%$$
$g$ increases by about $4\%$.
Solution by Sreeraj P, M.Sc Physics