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**[SOLVED] Electric potential and electric field**

## Homework Statement

A - 10.0 nC point charge and a + 20.0nC point charge are 15 cm apart on the x-axis.

What is the magnitude of the electric field at the point on the x-axis, between the charges, where the electric potential is zero?

## Homework Equations

sumE = E(of -10) + E (of 20)

E = kq/r^2

SumV = V(-10) +V(20)

V = kq/r

## The Attempt at a Solution

let the distance at which V = 0 between the charge be x

SumV = V(-10) +V(20) = 0

k { (-10 *10^-9/0.15 - x) + (20 *10^-9/ x)} = 0

solve for x

x = 0.1

0.15 - x = 0.05

SumE = E(-10) +E(20)

k { (-10 *10^-9/(0.15 - x)^2) + (20 *10^-9/ (x)^2)} = SumE

substitute x = 0.1

Sum E= 18000 V

i don't think this is the right answer

i think i am doing something wrong