JEE Mains Model Paper 21

A solid sphere of uniform density and radius R applies a gravitational force of attraction equal to F1 on a particle placed at a distance 3R from the centre of the sphere. A spherical cavity of radius R/2 is now made in the sphere as shown in the figure.The sphere with cavity now applies a gravitational force F2 on the same particle. The ratio F2∕F1 is