A coil of 5000 turns is wound on to a nonmagnetic toroid of

Question

A coil of 5000 turns is wound on to a nonmagnetic toroid of csa 100 cm², and mean circumference 0.5 m. A second coil of 1000 turns is wound over the first coil. If a current of 10 A flows through the first coil, determine

(a) the self-inductance of the first coil,

(b) the mutual inductance, assuming a coupling factor of 0.45, and

(c) the average emf induced in the second coil if interruption of the current causes the flux to decay to zero in 0.05 s.