I A very long solenoid of radius a, with It turns per unit length= carries a ctu'rent 13. A circular ring of wire with resistance R is coaxial with the solenoid at radius h I? a. when the current in the solenoid is gradually decreased, a current L is induced in the ring. (a) Calculate I: in terms of dIy'dt. (h) The power (ER) delivered to the ring must have come from the solenoid. Conrm this by calculating the pointing vector just outside the solenoid. Integrate over the entire surface of the solenoid and check that you recover the correct total power