Two planet of masses in the ratio 1:2, its radii in the ratio 1:2. Then the ratio of acceleration due to gravity will be ..........

Options

A. `1:2`
B. `2:1`
C. `3:5`
D. `5:3`

Answer

B

Explanation

`implies` According to `g = (GM)R^2`
`g_1/(g_2)=((M_1)/R_1^2)((R_2^2)/M^2)=(m_1/m_2)(R_2/R_1)^2 =(1/2)(2/1)^2`
`g_1/(g_(2))=4/2=2`
`g_1 : g_2 = 2:1 `