# Electric field strength at a point between charges

1. May 19, 2016

### Ch3m_

1. The problem statement, all variables and given/known data
A +1.0 μC charge is placed at point X. A +4.0 μC charge is placed at point Y,
50 cm from X.
How far from X, on the line XY, is the point where the electric field strength is zero?

2. Relevant equations
E = Q/4πε0r2

3. The attempt at a solution
I know that the electric field is zero at the point where the magnitude of the field due to the 1.0 μC charge is equal to the magnitude of the field due to the 4.0 μC charge, but I have tried making the equations equal to each other and don't know how to find r

2. May 19, 2016

### Incand

If you write up the equation the distances have to satisfy how does it look?
One hint is that if you define the distance from $X$ along the line as $x$ the distance from $Y$ can be written as $(0.5-x)$ (in meters).