Question

Current in a circuit falls from 5.0 A to 0.0 A in 0.1 s. If an average emfof 200 V induced, give an estimate of the self-inductance of the circuit.

Answer 1

Given: The initial current in the wire is 5.0 A, the final current in the wire is 0 A, the time taken for change is 0.1 s and the average emf is 200 V.

The average emf is given as,

e=L dI dt

Where, the self induction of the coil is L, the change in current is dI, the change in time is dt and the average emf is e.

By substituting the given values in above formula, we get

200=L ( 5−0 ) 0.1 L=4 H

Thus, the self induction of the coil is 4 H.