A rain drop falls near the surface of Earth with almost uniform velocity because
The force of viscosity of air balances its weight
Various forces acting on a drop during its descent are
(i)Its weightω, downwards
(ii)Buoyant force by air, upwards
(iii)Viscous force by air, upwards
Now when drop is falling with uniform velocity,
Forces are balanced [acceleration = 0]
⇒ω=FB+Fv
But due to very low density of air and very small size of the drop
FB≃0
⇒ω=Fv
Hence (c)