Assume we have a toroidal coil with a rectangular cross section, with an inner radius 1 cm, an outer radius 2 cm, a height of 1 cm and 1000 turns. The coil is connected to a resistor of 500 ohms. An AC current I(t) = Io cos(wt) with amplitude 0.5 A and frequency of 60 Hz flows through the wire.
a) What s the induced emf in the toroid? You can assume we are in the quasistatic regime. What is the current, I(t) in the resistor?
b) What is the back emf in the coil due to the current I(t) from the resistor? What is the ratio fo the amplitudes of this back emf and the "direct" emf in part a)?