3. DETAILS (a) Compute the energy density of the electric field. (Give your answer in n3/m.) nJ/m MY NOTES At a particular place on the surface of the Earth, the Earth's magnetic field has magnitude of 4.90 x 10-5 T, and there is also a 109 V/m electric field perpendicular to the Earth's surface. (b) Compute the energy density of the magnetic field. (Give your answer in 3/m.) pJ/m3 ASK YOUR TEACHER