A 2.50-cm-diameter parallel-plate capacitor with a spacing of 0.400 mm is charged to 100 V. Therefore the energy stored in this capacitor is 5.43 x 10^-8 J.

What is the energy density of this capacitor?

I've tried doing this problem by dividing energy by the volume, but I'm getting the answer 1770 J/m^3, which is wrong.

Question

A 2.50-cm-diameter parallel-plate capacitor with a spacing of 0.400 mm is charged to 100 V. Therefore the energy stored in this capacitor is 5.43 x 10^-8 J. 

What is the energy density of this capacitor?

I've tried doing this problem by dividing energy by the volume, but I'm getting the answer 1770 J/m^3, which is wrong.

sidsiddhartha · Answer

capacitence C is
$$C=\frac{ E0*A}{ D }$$
first find C
then 
energy=1/2*C*V^2