What is the electric field strength?

[rayhan619]

Homework Statement

50 pJ of energy is stored in a 2.0 cm*2.0 cm*2.0 cm region of uniform electric field.
What is the electric field strength?

Homework Equations

not sure

The Attempt at a Solution

not sure how to start this problem

 

[LowlyPion]

Maybe this will give you a start?
http://en.wikipedia.org/wiki/Electric_field#Energy_in_the_electric_field