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 \(0.4~\text{G}\). The induced emf between the axle and rim of the wheel will be:
\((1~\text{G}=10^{-4}~\text{T})\)
1. \(2.51 \times10^{-4}\) V
2. \(2.51 \times10^{-5}\) V
3. \(4.0 \times10^{-5}\) V
4. \(2.51\) V
A cycle wheel of radius \(0.5\) m is rotated with a constant angular velocity of \(10\) rad/s in a region of a magnetic field of \(0.1\) T which is perpendicular to the plane of the wheel. The EMF generated between its centre and the rim is:
1. \(0.25\) V
2. \(0.125\) V
3. \(0.5\) V
4. zero
A conducting square frame of side \(a\) and a long straight wire carrying current \(I\) are located in the same plane as shown in the figure. The frame moves to the right with a constant velocity \(v.\) The emf induced in the frame will be proportional to:
A thin semicircular conducting the ring \((PQR)\) of radius \(r\) is falling with its plane vertical in a horizontal magnetic field \(B,\) as shown in the figure. The potential difference developed across the ring when it moves with speed \(v\) is:
1. | zero |
2. | \(Bv\pi r^{2}/2\) and \(P\) is at a higher potential |
3. | \(\pi rvB\) and \(R\) is at a higher potential |
4. | \(2BvR\) and \(R\) is at higher potential |
1. | the rectangular, circular, and elliptical loops. |
2. | the circular and the elliptical loops. |
3. | only the elliptical loop. |
4. | any of the four loops. |
Initially plane of a coil is parallel to the uniform magnetic field B. If in time ∆t the coil is perpendicular to the magnetic field, then charge flows in ∆t depends on this time as:
1.
2.
3.
4.