Two identical solid copper spheres of radius R are placed in contact with each other. The gravitational attraction between them is proportional to :

Options

A. ` R^(2)`
B. ` R^(-2)`
C. ` R^(4)`
D. ` R^(-4)`

Answer

C

Explanation

F =` (G M M )/( R^(2))`
` = (G((4)/(3) pi R^(3)rho)((4)/(3) pi R^(3)rho))/(R^(2)) `
` therefore " " F prop R^(4) `