1. | \(BA\) and \(CD\) | 2. | \(AB\) and \(CD\) |
3. | \(BA\) and \(DC\) | 4. | \(AB\) and \(DC\) |
\(\mathrm A.\) | hold the sheet there if it is magnetic. |
\(\mathrm B.\) | hold the sheet there if it is non-magnetic. |
\(\mathrm C.\) | move the sheet away from the pole with uniform velocity if it is conducting. |
\(\mathrm D.\) | move the sheet away from the pole with uniform velocity if it is both, non-conducting and non-polar. |
1. | \(\mathrm A\) and \(\mathrm C\) only |
2. | \(\mathrm A\), \(\mathrm C\) and \(\mathrm D\) only |
3. | \(\mathrm C\) only |
4. | \(\mathrm B\) and \(\mathrm D\) only |
1. | \(2~\text{A}\) | 2. | \(0.25~\text{A}\) |
3. | \(1.5~\text{A}\) | 4. | \(1~\text{A}\) |
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
The magnetic flux linked with a coil (in Wb) is given by the equation \(\phi=5 t^2+3 t+60\). The magnitude of induced emf in the coil at \(t=4\) s will be:
1. \(33\) V
2. \(43\) V
3. \(108\) V
4. \(10\) 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. | \(1\) and zero in loop \(2\) | zero in loop
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. | \(1\) and not defined in loop \(2\) | zero in loop
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 |