Posted by **Beth** on Friday, March 8, 2013 at 4:48pm.

An electromagnetic wave has an electric field strength of 145 V/m at a point P in space at time t. (a) What is the electric field energy density at P? (b) A parallel-plate capacitor whose plates have area 0.110 m2 has a uniform electric field between its plates with the same energy density as the answer to part a. What is the charge on the capacitor?