A ball of radius r and density ρ falls freely under gravity through a distance h before entering water. Velocity of ball does not change even on entering water. If viscosity of water is η the value of h is given by
1
\( \frac{2}{9} r^{2}\left(\frac{1-\rho}{\eta}\right) g\)
2
\(\frac{2}{81} r^{2}\left(\frac{\rho-1}{\eta}\right) g\)
3
\(\frac{2}{81} r^{4}\left(\frac{\rho-1}{\eta}\right)^{2} g \)
4
\(\frac{2}{9} r^{4}\left(\frac{\rho-1}{\eta}\right)^{2} g\)