# Homework Help: Electric Potential Difference and electric field

1. Mar 24, 2013

### Soccerdude

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

A uniform electric field points in the –y direction with magnitude 325 V/m. Find the electric potential difference VB-VA between the points A at (-0.200, -0.300) m and B at (0.400, 0.500) m.

2. Relevant equations

∆V=-int(E . dl)
(Dot Product)

3. The attempt at a solution

∆V=-int(0,1)[(325)cos(36.87)dl]

∆V=-260[l](0,1)=-260 V

Am I doing this correctly?

2. Mar 24, 2013

### TSny

Yes. Looks like you chose a straight line path between the initial and final points, which is a good choice. Any path would do.

3. Mar 24, 2013

### Soccerdude

If I were to choose a different path, is this how I would set it up?

∆V=-(int(0,.6)[325cos(90)dl]+int(0,.8)[325cos(0)dl])

Much Appreciated

4. Mar 24, 2013

### TSny

Yes. Good. I noticed you switched the sign outside the integral for the part parallel to the y-axis which goes along with the angle of zero in the cosine. Alternately, of course, you could keep the negative sign in front, but use an angle of 180 degrees as you go upward against E.