Potential difference in uniform electric field

[lha08]

Homework Statement

A uniform electric field of magnitude 325 V/m is directed in the negative y direction. The coordinates of point A are (-0.200, -0.300) m and those of point B are (0.400, 0.500) m. Calculate the potential difference V(B)-V(A).

Homework Equations

The Attempt at a Solution

What I first did was that since the electric field is pointing towards the negative y direction, I think that I should use only the y component of the distance between Point A and B (0.8 m) and then use V(B)-V(A)= + E X distance. This gave me 260 V...I'm not sure but can anyone tell me if I'm doing it wrong and making a mistake somewhere?

 

[tiny-tim]

What I first did was that since the electric field is pointing towards the negative y direction, I think that I should use only the y component of the distance between Point A and B (0.8 m) and then use V(B)-V(A)= + E X distance. This gave me 260 V...I'm not sure but can anyone tell me if I'm doing it wrong and making a mistake somewhere?

Hi lha08!

Method looks ok …

electric potential = potential energy per charge,

and potential energy is just another name for (minus) the work done, which is force "dot" distance, or E.d.

E is in the y-direction, so E.d only uses the y-coordinate of distance (and be careful about the sign )