A small ball of mass m and density \(\rho\) is dropped in a viscous liquid of density \(\rho_{0}\). After sometime, the ball falls with constant velocity. The viscous force on the ball is :
(1) \(\operatorname{mg}\left(\frac{\rho_{0}}{\rho}-1\right)\)
(2) \(\operatorname{mg}\left(1+\frac{\rho}{\rho_{0}}\right)\)
(3) \( \operatorname{mg}\left(1-\rho \rho_{0}\right)\)
(4) \(\operatorname{mg}\left(1-\frac{\rho_{0}}{\rho}\right)\)