The network shown in the figure is part of a complete circuit. If at a certain instant, the current \(I\) is \(5~\text{A}\) and it is decreasing at a rate of \(5\times 10^{3}~\text{A/s}\), then \(V_B-V_A\)
1. | \(20~\text{V}\) | 2. | \(15~\text{V}\) |
3. | \(10~\text{V}\) | 4. | \(5~\text{V}\) |
1. | number of turns in the coil is reduced. |
2. | a capacitance of reactance \(X_C = X_L\) is included in the same circuit. |
3. | an iron rod is inserted in the coil. |
4. | frequency of the AC source is decreased. |
The inductance of a closed-packed coil of 400 turns is 8 mH. A current of 5 mA is passed through it. The magnetic flux through each turn of the coil is approximately-
1.
2.
3.
4.
The magnetic potential energy stored in a certain inductor is \(25~\text{mJ},\) when the current in the inductor is \(60~\text{mA}.\) This inductor is of inductance:
1. \(0.138~\text H\)
2. \(138.88~\text H\)
3. \(1.389~\text H\)
4. \(13.89~\text H\)
The current \((I)\) in the inductance is varying with time \((t)\) according to the plot shown in the figure.
1. | ![]() |
2. | ![]() |
3. | ![]() |
4. | ![]() |
The current in an inductor of self-inductance \(4~\text{H}\) changes from \(4~ \text{A}\) to \(2~\text{A}\) in \(1~ \text s\). The emf induced in the coil is:
1. \(-2~\text{V}\)
2. \(2~\text{V}\)
3. \(-4~\text{V}\)
4. \(8~\text{V}\)
1. | \(10~\text{J}\) | 2. | \(2.5~\text{J}\) |
3. | \(20~\text{J}\) | 4. | \(5~\text{J}\) |