Q. The acceleration due to gravity on a planet is same as that on earth and its radius is four times that of earth. What will be the value of escape velocity on that planet if it is $v_{e}$ on earth
A) $v_{e}$
B) $2v_{e}$
C) $4v_{e}$
D) $\frac{v_{e}}{2}$
Explanation
(b) $v = \sqrt{2gR} \Rightarrow \frac{v_{p}}{v_{e}} = \sqrt{\frac{g_{p}}{g_{e}} \times \frac{R_{p}}{R_{e}}} = \sqrt{1 \times 4} = 2$
$\therefore v_{p} = 2v_{e}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.