the distance to the left charge is x, the distance to the right charge is (1.5-x)
E=0=kQ1/x^2-kQ2/(1.5-x)^2
the second term is minus because E at the test point is in the opposite direction to the first E.
solve for x
A charge of 1.5uC is placed at the origin, and a charge of 3uC is placed at x = 1.5m. Locate the point between the two charges where the electric field is zero?
Q1 P Q2
x------------*-----------.
0
<---------1.5m----------->
1 answer