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 number of electrons attached to oil drop $X$?

• A. $1$
• B. $20$
• C. $40$
• D. $50$

Answer 1

The correct option is D $50$

From Millikan's oil drop experiment, lowest charge of a particle has been calculated.

Here charges on each particle are,

$X=0.04\times 50$
$Y=0.04$
$Z=0.04\times 20$

From the above data, it can be seen that $0.04$ is lowest possible charge. Hence, probable charge of electrons is $0.04C$.

No. of electrons of $X=50$
No. of electrons of $Y=1$
No. of electrons of $Z=20$