In an experiment replicating Millikan’s oil drop experiment, a pair of parallel plates are placed 0.0200 m apart and the top plate is positive. When the potential difference across the plates is 240.0 V, an oil drop of mass 2.0 × 10-11 kg gets suspended between the plates. (e = 1.6 × 10-19 C)

Question

(a) What is the charge on the oil drop?

(b) Is there an excess or deficit of electrons on the oil drop? How many electrons are in excess or deficit?

Answer 1

(a) The charge on the oil drop is 1.5 × 10-19 C.

(b) There is an excess of electrons on the oil drop. There are 9.375 × 1010 electrons in excess.