The value of `g` at a certain height `h` above the free surface of the earth is `x//4` where `x` is the value of `g` at the surface of the earth. The height `h` is

Options

A. `R`
B. `2R`
C. `3R`
D. `4R`

Answer

A

Explanation

`x=(GM)/(R^(2))`
Again,
`x/4=(GM)/((R+h)^(2))` or `x=GM(2/(R+h))^(2)`
`:. 1/(R^(2))=(2/(R+h))^(2)`
or `1/(R^(2))=2/(R+h)` or `R+h=2R` or `h=R`