1. The problem statement, all variables and given/known data A circular loop of wire can be used as a radio antenna. If an antenna with a diameter of 20.0 cm is located a distance of 2.40 km away from a from a source with a total power of 45.0 kW at a frequency of 101 MHz, what is the maximum emf induced in the loop? (Assume that the plane of the antenna loop is perpendicular to the direction of the radiation's magnetic field and that the source radiates uniformly in all directions.) 2. Relevant equations P = IA = cB^2/(2u) * 4 Pi r^2 Emf = -d(flux)/dt 3. The attempt at a solution I looked at the solutions and I had a questions about that. From P = IA, it solved for B = 2.42*10^-9, which I got. But then it says dB/dt = wB, w being angular frequency. Why?