A charged oil drop is held stationary in an electric field. The space containing the drop is exposed to a radioactive source and drop moves with different terminal velocities v, 2v, 30, 40 ....... etc. It suggests :

Options

A. the charge is quantised
B. the drop carries positive charge
C. the drop carries negative charge
D. charge is conserved.

Answer

A

Explanation

Here `q=(6pi eta r)/(E) (v_(0)+v)`
Now `v_(0)+v=V, 2V, 3V....etc`
`:. Q=((6 pi eta r)/(E))V. [(6pi eta r)/(E)]2V, [(6pi eta r)/(E)]3V....`
`=q.,2q,3q....`
Thus, charge is quantized.