In Millikan's oil drop experiment, what is the terminal speed of a speed of a drop of radius `2.0 xx 10^(5)m` and density `1.2xx10^(3)m^(-3)`? Take the viscosity of air at the temperature of the experimental to be `1.8xx10^(-5)Nsm^(2)`. How much is the viscous force on the drop at that speed? Neglect buoyancy of the drop due to air.

Explanation

`5.8 cm s^-1,3.9 times 10^-10 N`