The height at which the acceleration due to gravity becomes g/9 in terms of R. The radius of the earth is

Options

A. `(R)/(2)`
B. `sqrt(2)R`
C. `2R`
D. `(R)/(sqrt(2))`

Answer

C

Explanation

`g_(h)=(g)/((1+(h)/(R))^(2))=(g)/(9)implies(1+(h)/(R))^(2)=9`
`implies1+(h)/(R)=3impliesh=2R`