Two charges `5 xx 10^(-8) and -3 xx 10^(-8)`C are located 16 cm apart. At what points (s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.

Explanation

Let O be a point situated at a distance x cm from +ve charge of `5 xx 10^(-8)` C where the net electric potential is zero. For net potential to be zero
`V_1 + V_2 = 0`

Thus, `1/(4piepsi_0)[q_1/x+q_2/((r -x))] = 0 or 1/(4piepsi_0)[(5xx10^(-8))/x-(3xx10^(-8))/((16-x))]=0`
`rArr x = 10 cm`
Again point lies outside the charges at O., then
`or 1/(4piepsi_0) [(5xx 10^(-8))/x-(3xx10^(-8))/((x-16))] = 0`
`rArr x = 40 cm`