Two charges `5xx10^-8C and -3 xx 10^-8C` are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.

Explanation

Here `q_(1)=5xx10^-8C,q_(2)=-3xx10^-8C`
Let the potential be zero at a distance x cm from the charge `q_(1)=5xx10^-8C`.
`therefore r_(1)=x xx10^(-2)m`
`r_(2)=(16-x)xx10^(-2)m`
Now `V-(q_1)/(4piepsi_0r_1)+(q_2)/(4piepsi_0r_2)`
`=(1)/(4piepsi_0)[(q_1)/(r_1)+(q_2)/(r_2)] `
`therefore (q_1)/(q_2)=(-q_2)/(r_2)`
`=(5xx10^-8)/(x xx10^-2)= (-(-3xx10^-8))/((16-x)10^-2)` or (5)/(x)=(3)/(16-x)`
`3xx=80-5x`
`8x=80,x=10cm`