# Homework Help: Electric potential between two point charges

1. Feb 29, 2012

### drawar

1. The problem statement, all variables and given/known data
Two point charges are separated by a distance r. If the separation is reduced by a factor of 3/2, by what factor does the electric potential between them change?
A. 3/2
B. 2/3
C. 9/4
D. 4/9
E. Sqrt(3/2)

2. Relevant equations

3. The attempt at a solution
Honestly I couldn't think of any formula involving separation of 2 point charges and the electric potential between them. Reading a little more on electric potential, I find that U=Ed but then I'm not sure whether the strength of the electric field remain constant when we change the distance between two point charges.

2. Feb 29, 2012

### tiny-tim

hi drawar!
coulomb's law?

3. Feb 29, 2012

### drawar

Hi there!
I've just gone over it and still can't figure it out. Does the Coulomb's Law have anything to do with the electric potential?

4. Feb 29, 2012

### tiny-tim

indirectly …

can't you find the potential from the field?