Question

At what height from the surface of earth the gravitation potential and the value of $g$ are $-5.4\times {10}^{7}J{kg}^{-2}$ and $6.0{ms}^{-2}$ respectively? Take the radius of earth as $6400km$.

• A. $2600km$
• B. $1600km$
• C. $1400km$
• D. $2000km$

Answer 1

The correct option is A $2600km$

$V=-\frac{GM}{R+h}=-5.4\times {10}^7$ ....... (1)

$g=\frac{GM}{(R+h{)}^2}=6$ ...... (2)

Dividing the two equations, we get:

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

$\Rightarrow R+h=9000km$

$\Rightarrow h=2600km$