Q. A body of mass $m$ is moved to a height $h$ equal to the radius of the earth. The increase in potential energy is
A) $2\ mgR$
B) $mgR$
C) $mgR/2$
D) $mgR/4$
Explanation
(c) Increase in potential energy,
$\mathrm{\Delta}U = \frac{GMm}{(R + R)} - \left( - \frac{GMm}{R} \right)$
$= \frac{1}{2}\frac{GMm}{R} = \frac{1}{2}\left( \frac{GM}{R^{2}} \right)mR = \frac{1}{2}mgR$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.