Question

By changing the current of an inductor to 5A in 10s having inductance of 40mH, the induced emf will be

a )20mV
b)30mV
c)40mV
d )50mV​

Answer 1

Answer:

Electromagnetic Induction

Self Inductance

By a change of current from...

PHYSICS

By a change of current from 5 A to 10 A in 0.1 s, the self induced emf is 10 V. The change in the energy of the magnetic field of a coil will be

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ANSWER

∣ε∣=L

Δt

ΔI

L=

ΔI

∣ε∣Δt

=

(10−5)

10×0.1

=0.2H

The magnetic field energies for currents I

1

andI

2

are

U

1

=

2

1

LI

1

2

andU

2

=

2

1

LI

2

2

Change in energy = U

2

−U

1

ΔU=

2

1

LI

2

2

−

2

1

LI

1

2

=

2

L

(I

2

2

−I

1

2

)

ΔU=

2

0.02

(10

2

−5

2

)=7.5J