- 1(current)
Q. No.In the figure magnetic energy stored in the coil is:
| 1. | Zero | 2. | Infinite |
| 3. | \(25\) joules | 4. | None of the above |
1. \(\dfrac{E^{2}}{2 R}\)
2. \(\dfrac{E^{2} L}{2 R^{2}}\)
3. \(\dfrac{E^{2} L}{R}\)
4. \(\dfrac{E^{2} L}{2 R}\)
When the current in the portion of the circuit shown in the figure is \(2\) A and increases at the rate of \(1\) A/s, the measured potential difference \(V_{ab}=8\) V. However, when the current is \(2\) A and decreases at the rate of \(1\) A/s, the measured potential difference \(V_{ab}= 4\) V. The value of \(R\) and \(L\) is:
| 1. | \(3~\Omega\) and \(2~\text{H}\) respectively |
| 2. | \(3~\Omega\) and \(3~\text{H}\) respectively |
| 3. | \(2~\Omega\) and \(1~\text{H}\) respectively |
| 4. | \(3~\Omega\) and \(1~\text{H}\) respectively |
The figure shows three circuits with identical batteries, inductors, and resistors. Rank the circuits according to the current, in descending order, through the battery \((i)\) just after the switch is closed and \((ii)\) a long time later:
| 1. | \((i)~ i_2>i_3>i_1\left(i_1=0\right) (ii) ~i_2>i_3>i_1\) |
| 2. | \((i)~ i_2<i_3<i_1\left(i_1 \neq 0\right) (ii)~ i_2>i_3>i_1\) |
| 3. | \((i) ~i_2=i_3=i_1\left(i_1=0\right) (ii)~ i_2<i_3<i_1\) |
| 4. | \((i)~ i_2=i_3>i_1\left(i_1 \neq 0\right) (ii) ~i_2>i_3>i_1\) |
The network shown in figure is a part of a complete circuit. If at a certain instant, the current \(i\) is \(10\) A and is increasing at the rate of \(4\times 10^{3}\) A/sec, then \(V_A-V_B\) is:
| 1. | \(6\) V | 2. | \(-6\) V |
| 3. | \(10\) V | 4. | \(-10\) V |
In the circuit diagram shown in figure, \(R = 10~\Omega\), \(L = 5~\text{H},\) \(E = 20~\text{V}\) and \(i = 2~\text{A}\). This current is decreasing at a rate of \(1.0\) A/s. \(V_{ab}\) at this instant will be:
| 1. | \(40\) V | 2. | \(35\) V |
| 3. | \(30\) V | 4. | \(45\) V |
A series combination of inductance \((L)\) and resistance \((R)\) is connected to a battery of emf \(E\). The final value of current depends on:
| 1. | \(L\) and \(R\) | 2. | \(E\) and \(R\) |
| 3. | \(E\) and \(L\) | 4. | \(E\), \(L\), and \(R\) |
The resistance in the following circuit is increased at a particular instant. At this instant the value of resistance is \(10~\Omega.\) The current in the circuit will be:
| 1. | \(i = 0.5~\text{A}\) | 2. | \(i > 0.5~\text{A}\) |
| 3. | \(i < 0.5~\text{A}\) | 4. | \(i = 0\) |
Switch \(S\) of the circuit shown in the figure is closed at \(t=0\). If \(e\) denotes the induced emf in \(L\) and \(i\) denotes the current flowing through the circuit at time \(t\), then which of the following graphs is correct?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
An inductor is connected to a direct voltage source through a switch. Then:
| 1. | a very large emf is induced in inductor when the switch is closed. |
| 2. | a large emf is induced when the switch is opened. |
| 3. | a large emf is induced whether the switch is closed or opened. |
| 4. | no emf is induced whether the switch is closed or opened. |
- 1(current)
Q. No.
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