Q. No.1. \(2\)
2. \(3\)
3. \(5\)
4. \(10\)
1. \(150\) mA
2. \(300\) mA
3. \(250\) mA
4. \(100\) mA
Which of the following statements is true according to Lenz's law of electromagnetic induction?
| 1. | The induced EMF is such that it supports the change in magnetic flux. |
| 2. | The induced current flows in a direction that opposes the change that caused it. |
| 3. | When the magnetic flux through a coil changes rapidly, the magnitude of the induced EMF is smaller. |
| 4. | The induced charge passing through a circuit depends on the time over which the change in flux occurs. |
A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer \(G\) attached across the coil ?
Three positions shown describe : (a) the magnet's entry (b) magnet is completely inside and (c) magnet's exit.
| 1. |  |
| 2. |  |
| 3. |  |
| 4. |  |
| Assertion (A): | Lenz's law is in accordance with the conservation of energy. |
| Reason (R): | The amount of mechanical energy lost against the induced emf or current is equal to the electrical energy reappearing in the circuit. |
In the light of the above statements choose the correct answer from the options given below:
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
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The magnetic flux linked to a circular coil of radius \(R\) is given by:
\(\phi=2t^3+4t^2+2t+5\) Wb.
What is the magnitude of the induced EMF in the coil at \(t=5\) s?
| 1. | \(108\) V | 2. | \(197\) V |
| 3. | \(150\) V | 4. | \(192\) V |
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The magnetic flux through a circuit of resistance \(R\) changes by an amount \(\Delta \phi\) in a time \(\Delta t\). Then the total quantity of electric charge \(Q\) that passes any point in the circuit during the time \(\Delta t\) is represented by:
1. \(Q= \frac{\Delta \phi}{R}\)
2. \(Q= \frac{\Delta \phi}{\Delta t}\)
3. \(Q=R\cdot \frac{\Delta \phi}{\Delta t}\)
4. \(Q=\frac{1}{R}\cdot \frac{\Delta \phi}{\Delta t}\)
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Consider the given figure. What would you do to obtain a large deflection of the galvanometer?
| 1. | Use a rod made of soft iron inside the coil \(C_2\) |
| 2. | Connect the coil to a powerful battery |
| 3. | Move the arrangement rapidly towards the test coil \(C_1\) |
| 4. | All of the above |
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1. clockwise
2. anticlockwise
3. no current will be induced
4. dependent on the distance between the loops
| 1. | involves rotation of a coil in a magnetic field parallel to the axis of rotation of the coil. |
| 2. | involves rotation of a coil in a magnetic field perpendicular to the axis of rotation of the coil. |
| 3. | works in the principle of eddy currents. |
| 4. | involves just rotation of the coil and there is no need for an external electric or magnetic field. |
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