A charge \(Q\) is uniformly distributed on a ring of radius \(R\) made of an insulating material. If the ring rotates about the axis passing through its centre and normal to the plane of the ring with constant angular speed \(\omega\), then what will be the magnitude of the magnetic moment of the ring?
1. \(Q \omega R^{2}\)
2. \(\frac{1}{2} Q \omega R^{2}\)
3. \(Q \omega^{2} R\)
4. \(\frac{1}{2} Q\omega^{2} R\)
1. | \(10^{-5} ~\text{N} \), attractive |
2. | \(10^{-5}~\text{N} \), repulsive |
3. | \(2 \times 10^{-5}~\text{N} \), attractive |
4. | \(2 \times 10^{-5} ~\text{N} \), repulsive |
1. | Repulsive force of \(10^{-4}~\text{N/m}\) |
2. | Attractive force of \(10^{-4}~\text{N/m}\) |
3. | Repulsive force of \(2 \pi \times 10^{-5}~\text{N/m}\) |
4. | Attractive force of \(2 \pi \times 10^{-5}~\text{N/m}\) |
1. | putting in series resistance of \(240 ~\Omega \text {. }\) |
2. | putting in parallel resistance of \(240 ~\Omega \text {. }\) |
3. | putting in series resistance of \(15~ \Omega \text {. }\) |
4. | putting in parallel resistance of \(15~ \Omega \text {. }\) |
1. | \(nB\) | 2. | \(n^2B\) |
3. | \(2nB\) | 4. | \(2n^2B\) |
1. | infinite | 2. | zero |
3. | \( \frac{\mu_0 2 i}{4 \pi} ~\text{T} \) | 4. | \( \frac{\mu_0 i}{2 r} ~\text{T} \) |
1. | \(R \over 3\) | 2. | \(\sqrt{3}R\) |
3. | \(R \over \sqrt3\) | 4. | \(R \over 2\) |
A wire of length \(l\) carrying current \(i\) is folded to form a circular coil of \(N\) turns. What should be the value of \(N\) to have the maximum value of the magnetic moment in the coil?
1. \(1\)
2. \(4\)
3. \(9\)
4. \(10\)