Self Induction

Practice Questions:

Question 1: moderate

A varying current in a coil changes from 10 amp to zero in 0.5 sec. If average EMF is induced in
the coil is 220 volts, the self inductance of coil is :

1. 5 H

2. 10 H

3. 11 H

4. 12 H

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Question 2: moderate

How much length of a very thin wire is required to obtain a solenoid of length l0 and inductance L.

1. \[\sqrt{\frac{2\pi Ll_{0}}{\mu_{0}}}\]

2. \[\sqrt{\frac{4\pi Ll_{0}}{\mu_{0}^{2}}}\]

3. \[\sqrt{\frac{4\pi Ll_{0}}{\mu_{0}}}\]

4. \[\sqrt{\frac{8\pi Ll_{0}}{\mu_{0}}}\]

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Question 3: moderate

Which among the following unit represents henry?

1. \(\frac{\text{Volt (second)}^2}{\text{Ampere}}\)

2. \(\frac{\text{Volt-second}}{\text{Coulomb}}\)

3. \(\frac{\text{Volt-second}}{\text{Ampere}}\)

4. \(\frac{\text{Volt (second)}^3}{\text{Coulomb}}\)

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From induced emf \(e = L \frac{di}{dt}\), we have \(L = \frac{e dt}{di}\). Thus, the unit of inductance (henry) is equivalent to \(\frac{\text{Volt-second}}{\text{Ampere}}\).

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