A solid sphere of uniform density and radius $R$ applies a gravitational force of attraction equal to $F_1$ on a particle placed at $\mathrm{P}$, distance $2 R$ from the centre O of the sphere. A spherical cavity of the radius $\raisebox{1ex}{$R$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$ is now made in the sphere as shown in the figure.
The sphere with the cavity now applies a gravitational force $F_2$ on the same particle placed at $\mathrm{P}$.
The ratio $\raisebox{1ex}{$F_2$}\!\left/ \!\raisebox{-1ex}{$F_1$}\right.$ will be