A very long, straight solenoid with a diameter of 3.00 cm is wound with 40 turns of wire per centimeter, and the windings carry a current of 0.275 AS. A second coil having N turns and a larger diameter is slipped over the solenoid so that the two are coaxial. The current in the solenoid is ramped down to zero over a period of 0.50 s.
(a) What average emf is induced in the second coil if it has a diameter of 3.90 cm and N = 48? Express your answer in microvolts to two significant figures.
(b) What is the induced emf if the diameter is 7.80 cm and N = 96? Express your answer in volts to two significant figures.