In an oil drop experiment, the charges on oil drops were found as `1.5 xx 10^(-15), 3 xx 10^(-15), 4.5 xx 10^(-15), 6.0 xx 10^(-15)`. Calculate the magnitude of the charge on the electron.

Explanation

The magnitude of charge should be smallest & other charges should be integral multiples of that smallest charge( q = ne ). So in the problem, the smallest charge `1.5 xx 10^(-15)` and is also an integral multiple of all other charges.
case 1 : `1.5 xx 10^(-15) = 1 xx e`
case 2 : `3 xx 10^(-15) = 2 xx e`
case 3 : `4.5xx10^(-15) = 3 xx e`
case 4: `6xx10^(-15) = 4 xx e`
so charge on the electrons is same in all cases and it will be `1.5 xx 10^(-15)`