# Homework Help: Radial Electric Field

1. Mar 13, 2012

### chris_avfc

1. The problem statement, all variables and given/known data

Radial component of an electric field near charge 'q'.

E = (1 / 4∏ε) * (q/r^2)

Need to find the potential of this which is done through integrating this and taking the negative answer, i.e.

ΔV = -∫E dr

This is to be along a radial path towards the charge, starting from infinity to r2.

3. The attempt at a solution

So I have

ΔV = - (q/4∏ε) ∫1/r^2 dr

As the charge is constant.
Just unsure on the limits, I'm guessing its ∞ and r2, would that be right?

2. Mar 13, 2012

### ehild

$$\Delta V=V(r)-V(\infty)=-\frac{q}{4\pi \epsilon _0}\int_{\infty}^r{\frac{1}{r^2}dr}$$,

with V(∞)=0

ehild

3. Mar 13, 2012

### chris_avfc

Awesome, cheers mate. I had my limits the wrong way around.