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 $f_w=1000 \mathrm{~kg} \mathrm{~m}^{-3}$ and Density of air $f_a=1.2 \mathrm{~kg} \mathrm{~m}^{-3}, g=10 \mathrm{~m} / \mathrm{s}^2$ Coefficient of viscosity of air = $\left.1.8 \times 10^{-5} \mathrm{Nsm}^{-2}\right]$