A 200 W electric bulb emits light uniformly in all directions. The efficiency of the bulb (the fraction of the energy in the visible part of spectrum) is 4.5%. Find the rms value of the magnetic field in light at a distance of 51 cm from the bulb.

Ahuge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. the upper face carries +95.0 nc/m2 while the lower face carries -25.0 nc/ m2. what is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (ε0 = 8.85 × 10-12 c2/n · m2)