If `R` is the radius of the earth and `g` the acceleration due to gravity on the earth's surface, the mean density of the earth is

Options

A. `4pi G//3gR`
B. `3pi R//4gG`
C. `3g//4pi RG`
D. `piRg//12G`

Answer

c

Explanation

`g=(GM)/(R^(2))" and "M=(4)/(3)piR^(3)xxD`
`therefore" "g=((4//3)piR^(3)xxGD)/(R^(2))`
`therefore" "D=(3g)/(4piRG)`