A raindrop with radius R = 0.2 mm falls from a cloud at a height h = 2000 m above the ground. Assume that the drop is spherical throughout its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is :
[Density of water f_w = 1000 kg m^3 and Density of air f_a = 1.2 kg m^3, g = 10 m/s², Coefficient of viscosity of air = 1.8 10^5 Nsm^2]