Question

the self inductance of a inductive coil is 0.4H the current in the coil is decreasing at the rate of 2A per second what is the emf induced in the coil

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Answer 1

The current flowing in a coil of self-inductance 0.4 mH is increased by 250mA in 0.1 sec. the e.m.f. induced.

Answer 2

Given :

Self inductance (L) = 0.4 H

Rate of change of current ($\frac{di}{dt}$) = 2A

To Find :

EMF induced in the coil

Solution :

The induced EMF (E)  in an inducting coil can be given as -

Emf induced in a coil (E) = -L $\frac{di}{dt}$

Here negative sign is because the induced emf opposes the rate of change of current.

EMF induced in the coil (E) = L$\frac{di}{dt}$

                                             = 0.4 × 2

                                             = 0.8 V

Therefore, the EMF induced in the coil is 0.8 V.