Q. No.An emf is generated by an ac generator having \(100\) turn coil, of loop area \(1\) m2. The coil rotates at a speed of one revolution per second and placed in a uniform magnetic field of \(0.05\) T perpendicular to the axis of rotation of the coil. The maximum value of emf is:
1. \(3.14\) V
2. \(31.4\) V
3. \(62.8\) V
4. \(6.28\) V
1. \(8~\mathrm{\mu J}\)
2. \(4~\mathrm{\mu J}\)
3. \(4~\mathrm{mJ}\)
4. \(8~\mathrm{mJ}\)
\(\phi=2t^3+4t^2+2t+5\) Wb.
The magnitude of induced emf in the coil at \(t=5\) s is:
1. \(108\) V
2. \(197\) V
3. \(150\) V
4. \(192\) V
An inductor coil of self-inductance \(10~\mathrm H\) carries a current of \(1~\mathrm A\) . The magnetic field energy stored in the coil is:
| 1. | \(10~\mathrm J\) | 2. | \(2.5~\mathrm J\) |
| 3. | \(20~\mathrm J\) | 4. | \(5~\mathrm J\) |
The dimensions of mutual inductance \((M)\) are:
1. \(\left[M^2LT^{-2}A^{-2}\right]\)
2. \(\left[MLT^{-2}A^{2}\right]\)
3. \(\left[M^{2}L^{2}T^{-2}A^{2}\right]\)
4. \(\left[ML^{2}T^{-2}A^{-2}\right]\)
The current in an inductor of self-inductance \(4~\text{H}\) changes from \(4~ \text{A}\) to \(2~\text{A}\) in \(1~ \text s\). The emf induced in the coil is:
1. \(-2~\text{V}\)
2. \(2~\text{V}\)
3. \(-4~\text{V}\)
4. \(8~\text{V}\)
1. \(2~\text{A}\)
2. \(0.25~\text{A}\)
3. \(1.5~\text{A}\)
4. \(1~\text{A}\)
| 1. | \(0\) | 2. | \(2\) weber |
| 3. | \(0.5\) weber | 4. | \(1\) weber |
A wheel with \(20\) metallic spokes, each \(1\) m long, is rotated with a speed of \(120\) rpm in a plane perpendicular to a magnetic field of \(0.4\) G. The induced emf between the axle and rim of the wheel will be:
\((1~\mathrm{G}=10^{-4}~\mathrm{T})\)
1. \(2.51 \times10^{-4}\) V
2. \(2.51 \times10^{-5}\) V
3. \(4.0 \times10^{-5}\) V
4. \(2.51\) 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
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