Q. No.A Rowland ring of mean radius \(15\) cm has \(3500\) turns of wire wound on a ferromagnetic core of relative permeability \(800.\) What is the magnetic field \(B\) in the core for a magnetizing current of \(1.2\) A?
1. \(3.27\) T
2. \(2.56\) T
3. \(1.05\) T
4. \(4.48\) T
1. \(1~\text J\)
2. \(2~\text J\)
3. \(3~\text J\)
4. \(4~\text J\)
Which of the following, is independent of \(\theta?\)
| 1. | \(E_B\cdot\tau_B\) | 2. | \(\dfrac{E_B}{\tau_B}\) |
| 3. | \(E_B^2+\tau_B^2\) | 4. | \(E_B^2-\tau_B^2\) |
1. \( B=\mu_{0}\left(H+I\right)\)
2. \(I=\mu_0\left(H+B\right)\)
3. \(H=\mu_0\left(I+B\right)\)
4. \(B=2H\left(I+\mu_0\right)\)
| 1. | attractive. |
| 2. | repulsive. |
| 3. | zero. |
| 4. | any of the above depending on the external field \(B\) and the sample separation. |
| Assertion (A): | When a magnet is brought near iron nails, only translatory force acts on it. |
| Reason (R): | The field due to a magnet is generally uniform. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
A bar magnet of length \(l\) and magnetic moment \(p_{m}\) is bent in the form of an arc as shown in the figure below. The new magnetic dipole moment will be:
| 1. | \(p_{m}\) | 2. | \(\dfrac{3}{\pi }p_{m}\) |
| 3. | \(\dfrac{2}{\pi }p_{m}\) | 4. | \(\dfrac{1}{2 }p_{m}\) |
A solenoid has a core of material with relative permeability \(400.\) The windings of the solenoid are insulated from the core and carry a current of \(2~\text A.\) If the number of turns is \(1000\) per metre, the magnetic field intensity \(H\) is:
1. \(2\times10^2~\text{A/m}\)
2. \(2\times10^3~\text{A/m}\)
3. \(2~\text{A/m}\)
4. \(20~\text{A/m}\)
A regular array of identical vertical current-carrying wires, each passing through a horizontal table, is arranged as shown in the figure (with the direction of current flow indicated). Where are diamagnetic particles most likely to accumulate if they are scattered on the table?
| 1. | Around regions such as \(A.\) |
| 2. | Around regions such as \(B.\) |
| 3. | In circular regions around individual wires such as \(C.\) |
| 4. | Uniformly everywhere. |
1. \(0.064~\text{J}\)
2. \(-0.064~\text{J}\)
3. zero
4. \(-0.082~\text{J}\)
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