Q- An aluminum ring of radius r₁ and resistance R is placed around the top of a long air-core solenoid with n turns per meter and smaller radius r₂ as shown in Figure. Assume that the axial component of the field produced by the solenoid over the area of the end of the solenoid is one-half as strong as at the solenoid's center. Assume that the solenoid produces negligible field outside its cross-sectional area. The current in the solenoid is increasing at a rate of dI/dt.

(a) What is the induced current in the ring?

(b) At the center of the ring, what is the magnetic field produced by the induced current in the ring?

Solution: