# Uniform, non-zero electric field

1. Apr 11, 2010

### A_lilah

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

At x = 1.00 m, the voltage is 4.00 V. At x = 3.00 m, the voltage is also 4.00 V. Assuming that there is a steady, uniform non-zero electric field over this entire region, give four possible directions of that electric field.

2. Relevant equations

E = (delta V)/d
Ue = qV
(the electric potential = charge * voltage)

I'm not entirely sure, these are just the ones that sort of relate the electric field with voltage.

3. The attempt at a solution

For these charges to have an equal voltage in the electric field, the force of the electric field * the distance between either charge and one of the plates should = 0 (from the first equation above), so anywhere in the field where they are at the same y coordinate (in line with each other), they should have the same voltage. This gives me two directions for the field- it can point up or down (switching the positive and negative plates) and the voltages could be the same:

- - - - - - - -
____________ <-- negative plate

^ ^ ^ ^ <---direction 1
--(1m)----(3m)------------------->x axis
____________ <-- positive plate
+ + + + + + +

and if you switch the negative and positive plates, the field points down, my second direction, but I don't see how you could have two additional directions, so perhaps I am thinking about this wrong. Any insight would be great! thanks

2. Apr 12, 2010

### tiny-tim

Hi A_lilah!

(have a delta: ∆ )

Hint: if a uniform electric field is North, where are the lines (or surfaces) of equal voltage (equal electric potental)?

3. Apr 12, 2010

### A_lilah

I'm not sure I understand what you mean by north~ do you mean pointing upwards? The equipotential lines are perpendicular to the electric field lines...

4. Apr 12, 2010

### tiny-tim

That's right.

So …