Self Induction

Q.

A wire of fixed length is wound on a solenoid of length $l$ and radius $R$. Its Self Inductance is found to be $L$. Now, if the same wire is wound on a solenoid of length $\frac{I}{2}$ and radius $\frac{R}{2}$, then self inductance will be

Q. A coil is wound as a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor 2 and the number of turns per unit length of the coil remain the same, the self inductance increases by a factor of

1. 16
2. 12
3. 8
4. 4

Q. An emf of 2 volt is produced in a coil when the current changes at a steady rate from 3 to 2 ampers 1 milli – second. The value of self inductance of the coil will be

1. Zero
2. 2 mH
3. 2 H
4. 200 mH

Q.

The equivalent quantity of mass in electricity is

1. Charge

2. Potential

3. Inductance

4. Current

Q.

Two different coils have self-inductance $L_1$ = 8mH and $L_2$ = 2mH respectively. The current in both the coils is increased at a same rate. At a certain instant of time, the power being supplied to both the coils is equal. At that instant, the current, the induced voltage, and the energy stored in $L_1$ and $L_2$ are $I_1$ and $I_2$, $V_1$ and $V_2$, and $W_1$ and $W_2$ respectively. Then

1. $\frac{i_1}{i_2}=\frac{1}{4}$

2. $\frac{i_1}{i_2}=48$

3. $\frac{W_2}{W_1}=4$

4. $\frac{V_2}{V_1}=\frac{1}{4}$

Q.

The coefficient of self inductance of a solenoid is $0.18$ mH. If a rod of soft iron of relative permeability 900 is inserted in it, then the coefficient of self inductance will become nearly

1. 5.4 mH

2. 162 mH

3. 0.006 mH

4. 0.0002 mH

Q. The back e.m.f. induced in a coil, when current changes from 1 ampere to zero in one millisecond, is 4 volts, the self inductance of the coil is

1. 1 H
2. 4 H
3. ${10}^{-3}$ H
4. $4\times {10}^{-3}$ H

Q. $1000$ identical drops of mercury are charged to the same potential at $10\text{V}$. All these are now combined to make one large drop. The potential of the large drop is

1. $100\text{V}$
2. $10\text{V}$
3. $1000\text{V}$
4. $90\text{V}$

Q. An emf of $5\text{V}$ is produced by an inductor due to self inductance, when the current changes at a steady rate from $3\text{A}$ to $2\text{A}$ in $1\text{ms}$. The value of self inductance of inductor is

1. $\text{Zero}$
2. $0.5\text{H}$
3. $50\text{H}$
4. $5\text{mH}$

Q. A coil of 100 turns carries a current of 5mA and creates a magnetic flux of ${10}^{-5}$ Weber. The inductance is

1. 0.2H
2. 2mH
3. 2H
4. 0.2mH

Q. Current in a coil increases from 0 to 1 ampere in 0.1 second. If self inductance of the coil is 5 millihenry, magnitude of induced emf is

1. $5V$
2. $5\times {10}^{-3}V$
3. $0.5V$
4. $5\times {10}^{-2}V$

Q. A magnetic flux of $5\mu \text{Wb}$ is linked with a coil when a current of $1\text{mA}$ flows through it. Find the self inductance of the coil?

1. $2\text{mH}$
2. $3\text{mH}$
3. $4\text{mH}$
4. $5\text{mH}$

Q. If the number of turns per unit length of a coil of a solenoid is tripled, then the self – inductance of the solenoid will becomes

1. Nine times
2. Remain constant
3. Halved
4. Doubled

Q. A coil is wound as a transformer of rectangular cross-section. If all the linear dimensions of the transformer are increased by a factor 2 and the number of turns per unit length of the coil remain the same, the self inductance increases by a factor of

1. 16
2. 12
3. 8
4. 4

Q. An emf of $5\text{V}$ is produced by an inductor due to self inductance, when the current changes at a steady rate from $3\text{A}$ to $2\text{A}$ in $1\text{ms}$. The value of self inductance of inductor is

1. $\text{Zero}$
2. $0.5\text{H}$
3. $50\text{H}$
4. $5\text{mH}$