Two planets have radii r1 and r2 and densities d1 and d2respectively. The ratio of the gravitational force on them will be:

Force of attraction between two masses= F=Mg=GM2r2; here universal gravitation constant=G; mass=\M; distance=r mass=M=4π3r3d d=density F=G4π3r3d2r2 F∝d2r4 F1F2=d1d22×r1r24