Q. No.| 1. | \(1:2\) | 2. | \(2:1\) |
| 3. | \(8:1\) | 4. | \(1:8\) |
1. \(2~\text{H}\)
2. \(4~\text{H}\)
3. \(8~\text{H}\)
4. \(12~\text{H}\)
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.
1. \(8~\mu \text{J}\)
2. \(4~\mu \text{J}\)
3. \(4~\text{mJ}\)
4. \(8~\text{mJ}\)
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.
Which one of the following is the correct variation of voltage with time in the coil?
| 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. | \(5~\text{J}\) |
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