question_answer 3)

A long solenoid with 15 turns per cm has a small loop of area placed inside the solenoid normal to its axis. If the current carried by the solenoid changes steadily from 2.0 A to 4.0 A in 0.1 s, what is the induced e.m.f. in the loop while the current is changing?  

Answer:

Usingwe get                                 But                                                  in 1 m length the no. of turns are 15 x 100)                 Then                 (loop has only one turn)