Q 11-07-030NEETJEE MainMedium
A planet has twice the radius of the Earth and the same mass. The escape velocity from its surface, in terms of that from the Earth $v_e$, is
Answer: (B) $\dfrac{v_e}{\sqrt{2}}$
Concept. Same mass: $v_e \propto \dfrac{1}{\sqrt R}$.
Step 1. Scale. $v' = \dfrac{v_e}{\sqrt2}$.
Answer. $\dfrac{v_e}{\sqrt2}$ (Option B).
Solution by Sreeraj P, M.Sc Physics