Question

Describe Millikan's Oil Drop experiment in brief.

Answer 1

Millikan's Oil Drop experiment:

• Some fine oil droplets were allowed to be sprayed into the chamber by an atomizer.
• The air in the chamber was subjected to ionization by X rays. Electrons produced by the ionization of air attracted themselves to the oil drop.
• When a sufficient amount of electric field is applied which can balance the gravitational force acting on an oil drop, the drop remains suspended in the air.
• Millikan observed that the smallest charge found was approximately $1.59\times {10}^{-19}$Coulomb and the charge on each drop was always an integral multiple of that value.
• On the basis of this observation, he concluded that $1.59\times {10}^{-19}$Coulomb is the smallest possible charge and consider that value as the charge of the electron.