Neet Solved Paper 2013 Question 10
Question: A body of mass m taken from the earth’s surface to the height equal to twice the radius (R) of the earth. The change is potential energy of body will be
Options:
A) $ mg2R $
B) $ \frac{2}{3}mgR $
C) $ 3mgR $
D) $ \frac{1}{3}mgR $
Show Answer
Answer:
Correct Answer: B
Solution:
Change in potential energy $ \Delta U=-\frac{GMm}{R+2R}-( -\frac{GMm}{R} ) $
$ =-\frac{GMm}{3R}+\frac{GMm}{R} $ $ =\frac{2GMm}{3R}=\frac{2}{3}mgR $ $ [ \because g=\frac{GM}{R^{2}} ] $
