| 1. | zero | 2. | \(2\) Wb |
| 3. | \(0.5\) Wb | 4. | \(1\) Wb |
In a coil of resistance \(10\) \(\Omega\), the induced current developed by changing magnetic flux through it is shown in the figure as a function of time. The magnitude of change in flux through the coil in Weber is:
| 1. | \(2\) | 2. | \(6\) |
| 3. | \(4\) | 4. | \(8\) |
| 1. | \(0.125 \pi~ \text{mV}\) | 2. | \(125 \pi ~\text{mV}\) |
| 3. | \(125 \pi~\text{V}\) | 4. | \(12.5 \pi~\text{mV}\) |
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 |
A \(800\) turn coil of effective area \(0.05~\text{m}^2\) is kept perpendicular to a magnetic field \(5\times 10^{-5}~\text{T}\). When the plane of the coil is rotated by \(90^{\circ}\)around any of its coplanar axis in \(0.1~\text{s}\), the emf induced in the coil will be:
| 1. | \(0.02~\text{V}\) | 2. | \(2~\text{V}\) |
| 3. | \(0.2~\text{V}\) | 4. | \(2\times 10^{-3}~\text{V}\) |
A long solenoid of diameter \(0.1\) m has \(2 \times 10^4\) turns per meter. At the center of the solenoid, a coil of \(100\) turns and radius \(0.01\) m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to \(0\) A from \(4\) A in \(0.05\) s. If the resistance of the coil is \(10\pi^2~\Omega\), then the total charge flowing through the coil during this time is:
1. \(16~\mu \text{C}\)
2. \(32~\mu \text{C}\)
3. \(16\pi~\mu \text{C}\)
4. \(32\pi~\mu \text{C}\)
A uniform magnetic field is restricted within a region of radius \(r\). The magnetic field changes with time at a rate \(\frac{dB}{dt}\). Loop \(1\) of radius \(R>r\) is enclosed within the region \(r\) and loop \(2\) of radius \(R\) is outside the region of the magnetic field as shown in the figure. Then, the emf generated is:
| 1. | zero in loop \(1\) and zero in loop \(2\) |
| 2. | \(-\frac{dB}{dt}\pi r^2\) in loop \(1\) and zero in loop \(2\) |
| 3. | \(-\frac{dB}{dt}\pi R^2\) in loop \(1\) and zero in loop \(2\) |
| 4. | zero in loop \(1\) and not defined in loop \(2\) |
An electron moves on a straight-line path \(XY\) as shown. The \({abcd}\) is a coil adjacent to the path of electrons. What will be the direction of current if any, induced in the coil?
| 1. | \({abcd}\) |
| 2. | \({adcb}\) |
| 3. | The current will reverse its direction as the electron goes past the coil |
| 4. | No current included |
| 1. | twice per revolution. |
| 2. | four times per revolution. |
| 3. | six times per revolution. |
| 4. | once per revolution. |
| 1. | \(\Large\frac{B\omega L^2}{8}\) | 2. | \(\Large\frac{B\omega L^2}{2}\) |
| 3. | \(\Large\frac{B\omega L^2}{4}\) | 4. | zero |