At what height from the surface of earth will the value of g be reduced by `36%` from the value on the surface? Take radius of earth `R = 6400 km`.

Options

A. 1200 km
B. 1600 km
C. 2000 km
D. 2200 km

Answer

B

Explanation

`(g')/(g)=(64)/(100)` but `(g')/(g)=(R^(2))/((R+h)^(2))`
`therefore (R )/(R+h)=(8)/(10) " " therefore h = (R )/(4) = 1600 km`