# What is the potential difference VA-VB?

1. Feb 20, 2006

### hoseA

Points A (3 m, 2 m) and B (6 m, 6 m) are in a
region where the electric field is uniform and
given by E = Exi + Eyj, where Ex = 3 N/C
and Ey = 2 N/C.
What is the potential difference VA-VB?

I used E(rB-rA)

sqr rt(13) times (sqr rt (72) - sqr rt (13)) = 17.59

this is wrong. What am i doing wrong?

2. Feb 20, 2006

### neutrino

Given the field do you know how to calculate the potential (difference) in terms of a line intergral?

3. Feb 21, 2006

### hoseA

help within the hour is much appreciated... I'm thinking maybe it should be negative?

4. Feb 21, 2006

### nrqed

For a uniform E field, the potential difference is given by a scalar product (NOT a product of magnitudes!), $$\Delta V = - \vec E \cdot \vec r$$

Pat