Equipotential surfaces electric field problem

[wildredhead]

Homework Statement

A given system has the equipotential surfaces shown in the figure
What is the magnitude of the electric field?
What is the direction of the electric field? (degrees from + x axis
What is the shortest distance one can move to undergo a change in potential of 5.00

Homework Equations

E= V/d

The Attempt at a Solution

I seem to be getting the same answer and its wrong I used the pythagoreon therom to find distances of each and divided the volts by the respecitive distances. I do not know what I am doing wrong I keep getting 2.24*10^2 V/m. Moreover, when I do the angle part I just do some trig and use that. Either way I try to do it and get 26.6 or 63.2. What am I doing wrong? Is the first part just the slope

 

[rl.bhat]

Where is the figure?

 

[merryjman]

I can't see the figure yet either, but unless you're dealing with a uniform electric field then you can't use the equation you listed. As you said, electric field is the slope of a potential vs. position graph. If you're using calculus, it's the derivative with respect to position.

 

[wildredhead]

I think I uploaded it now. Sorry!
It is an attachment

 

[rl.bhat]

Slope of the equipotential lines is tan(theta) = 2/4 = 1.2.
Find theta.
Distance between the equipotential lines d is x*sin(theta). Here x = 4 cm.

 

[wildredhead]

SO part A is the slope = -1/2? But when I do tan^-1 (2/4) I still get 26.6. What am I doing wrong?

 

[vela]

What is the relationship between the directions of the electric field and the equipotential lines?