If radius of earth is `R`, then the height h at which the value of `g` becomes (1/49)th of its value at the surface is

Options

A. 2R
B. 3R
C. 6R
D. 4R

Answer

C

Explanation

With height, `g'=(g)/((1+(h)/(R))^(2))`
Given, `g'=(g)/(49)`
`:. (g)/(49)=(g)/((1+(h)/(R))^(2))rArr(1)/(49)=(1)/((1+(h)/(R))^(2))`
`rArr 49=(1+(h)/(R))^(2)`
`rArr7=1+(h)/(R)rArrh=6R`.