Question

A positive charge +q is located to the left of a negative charge -q. On a lne passing through the two charges there are two places where the total potential is zero. The first place is between the charges and is 3.8 cm to the left of the negative charge. The second place is 7.8 cm to the right of the negative charge.
1. What is the distance between the charges (in cm)?
2. What is the +q/-q ratio of the magnitude of the charges?

Answer 1

1.E1=E2,x^2_7.6x+3.8^2=3.8^2,x_7.6=0,x=7.6,where x is the distance separating q and -q

2.the ratio q\-q is equal to -1