Question

In Millikan's oil drop experiment, the charge of three oil drops X, Y, and Z have been found to be 2, 0.04 and 0.8 respectively. What could be the probable charge of an electron and the number of electrons attached to these oil drops?

• A. 0.04C, 50, 1, 20
• B. 0.04C, 50, 2, 20
• C. 0.8C, 20, 15, 50
• D. 0.8C, 1, 50, 23

Answer 1

The correct option is A 0.04C, 50, 1, 20

The magnitude of the charge should be smallest and other charges should be integral multiples of that smallest charge.

So, in the data given here, the smallest charge is 0.04 and all other charges are an integral multiple of it. Therefore, The charge on electron( e) = 0.04C

We know that $q=ne$ (n=1,2,3.....) & $e=0.04$

Calculating the value of n ( no of electrons)

When q=2, then n comes out to be 50

When q=0.04 , n = 1

When q=0.8 , n = 20