What is the electric field magnitude at points where electric potential is zero?

[n_h0987]

Homework Statement

A -14.3 nC point charge and a +24.9 nC point charge are 17.4 cm apart on the x-axis. What is the magnitude of the electric field at the two points on the x-axis where the electric potential is zero?

Homework Equations

V = kq/r
E = kq/r^2

The Attempt at a Solution

Since the potential = 0,

q1 = -14.3 nC, q2 = 24.9 nC

kq1/(r+0.174) = kq2/r

But this gives me one negative value for r, whereas I need two values.

 

[WatermelonPig]

Electric potential is a scalar.

 

[darkxponent]

since net potential is zero then

Potential due to q1 + potential due to q2=0

means equation is

kq1/(r+0.174) + kq2/r = 0 ; {not kq1/(r+0.174) = kq2/r}this will give two values of r one negative and one positive

 

[n_h0987]

I figured it out, thank you!