If the density of a small planet is the same as that of earth while the radius of the planet is `0.2` times that of the earth the gravitational on the surface of that planet is :

Options

A. 0.2 g
B. 0.4 g
C. 2g
D. 4g

Answer

A

Explanation

`g=4/3piGRrho`
`and g'4/3 piGR'rho`
`therefore(g')/(g) =(R')/(R)=0.2`
`g'=0.2g`