What is the energy density of the electric field ?

[pr_angeleyes]

Two large non-conducting plates of surface area A = 0.25 m^2 carry equal but opposite charges Q = 75 uC. What is the energy density of the electric field between the two plates?


My attempt:

E=(charge density)/epsilon

And
U=1/2*epsilon*E^2

So
U=0.5(charge density)^2/epsilon

=0.5*(75*10^-6/0.25)^2/(8.85*10^-12)

=5084.75J/m^3 = 5.1 x 10^3 J/m^3

is this right?

 

[dreamLord]

Your formulas look correct, can't say about the calculations.