Q. If $g$ is the acceleration due to gravity on the surface of the earth, the gain in potential energy of an object of mass $m$ raised from the earth’s surface to a height equal to the radius $R$ of the earth is
A) $\frac{mgR}{4}$
B) $\frac{mgR}{2}$
C) $mgR$
D) $2mgR$
Explanation
(b) $\ \ \ \ \ \ \ \ \ \ \ \mathrm{\Delta}U = \frac{mgh}{1 + \frac{h}{R}} = \frac{mgh}{1 + \frac{R}{R}} = \frac{mgR}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.