### NEET Solved Paper 2016 Question 7

##### Question: At what height from the surface of earth the gravitation potential and the value of g are $ 5.4\times 10^{7}\text{ J k}{g^{2}} $ and $ 6.0\text{ m}{s^{2}} $ respectively? Take the radius of earth as 6400 km:

#### Options:

A) 2600 km

B) 1600 km

C) 1400 km

D) 2000 km

## Show Answer

#### Answer:

Correct Answer: A

#### Solution:

- $ V=\frac{-GM}{R+h}=-5.4\times 10^{7} $ ??(1) and $ g=\frac{GM}{{{(R+h)}^{2}}}=6 $ ??(2) dividing (1) and (2)

$ \Rightarrow $ $ \frac{5.4\times 10^{7}}{(R+h)}=6 $

$ \Rightarrow $ $ R+h=9000,km $ so $ h=2600,km $