Q. No.1. \(6~\text{Wb}\)
2. \(2~\text{Wb}\)
3. \(8~\text{Wb}\)
4. \(4~\text{Wb}\)
The magnetic flux through a circular loop varies with time according to the given equation:
\(\phi=(5 t^2-3 t+5) ,\)
where \(\phi\) is in webers and \(t\) is in seconds.
If the resistance of the loop is \( 8~\Omega,\) what is the current in the loop at \(t=2 ~\text s \text{?}\)
| 1. | \( \dfrac{15}{8}~\text{A}\) | 2. | \( \dfrac{5}{8}~\text{A}\) |
| 3. | \( \dfrac{17}{8}~\text{A}\) | 4. | \(\dfrac{13}{8}~\text{A}\) |
1. \(10^{-1}\)
2. \(10^{-2}\)
3. \(10^{-3}\)
4. \(10\)
1. \(90~\text{V}\)
2. \(120~\text{V}\)
3. \(220~\text{V}\)
4. \(30~\text{V}\)
In a coil of resistance \(100~\Omega\), a current is induced by changing the magnetic flux through it (as shown in the graph). The magnitude of the change in the flux through the coil is:
1. \(200~\text{Wb}\)
2. \(225~\text{Wb}\)
3. \(250~\text{Wb}\)
4. \(275~\text{Wb}\)
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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