Q. No.A material when heated suddenly changes its magnetic property at a particular temperature and above this temperature, its susceptibility is found to be inversely proportional to the absolute temperature. The material may be:
1. Ferromagnetic
2. Diamagnetic
3. Paramagnetic
4. Ferromagnetic or Paramagnetic
As we go from the magnetic equator towards the geographic south pole, the angle of the dip will become:
| 1. | More and more vertically downward and perpendicular to the surface at the magnetic pole. |
| 2. | More and more vertically upward and perpendicular to the surface at the magnetic pole. |
| 3. | Less and less vertically downward and horizontal at the magnetic pole. |
| 4. | Less and less vertically upward and horizontal at the magnetic pole. |
A long solenoid has 1500 turns per metre and an iron core of = 1100 is kept inside it. 2A current flows in the coil of the solenoid. If the core is heated beyond curie temperature, then:
| 1. | The H and B fields in the solenoid reduce to zero. |
| 2. | The H and B fields in the solenoid remain unchanged. |
| 3. | The H field in the solenoid is nearly unchanged but B field decreases significantly. |
| 4. | The B field in the solenoid is nearly unchanged but the H field decreases significantly. |
Choose the correct statement regarding magnetism.
| 1. | Paramagnetic sample displays greater magnetization when cooled. |
| 2. | Diamagnetism is almost independent of temperature. |
| 3. | Ferromagnetic substances show hysteresis. |
| 4. | All of these. |
The material suitable for making electromagnets should have:
1. High retentivity and high coercivity
2. High retentivity and low coercivity
3. Low retentivity and high coercivity
4. Low retentivity and low coercivity
A Gaussian surface is drawn enclosing the N-pole of a bar magnet. The net magnetic flux through the Gaussian surface will be:
(pole strength of N-pole is treated as positive and S-pole as negative)
| 1. | positive. |
| 2. | negative. |
| 3. | positive or negative. |
| 4. | zero. |
The magnetization of a piece of iron or steel:
| 1. | depends on the strength of the magnetizing field. |
| 2. | depends on external conditions such as temperature. |
| 3. | cannot be done beyond the saturation point. |
| 4. | all of these. |
If a bar magnet is kept on a horizontal plane with N-pole of bar magnet facing geographic N-pole and S-pole of bar magnet facing geographic S-pole, then the number of neutral points is:
| 1. | 0 | 2. | 1 |
| 3. | 2 | 4. | Infinite |
When a magnetic material is subjected to a very small magnetising force \(H,\) the intensity of magnetisation is proportional to:
| 1. | \(\frac{1}{\sqrt{H}} \) | 2. | \(\sqrt{H} \) |
| 3. | \(H \) | 4. | \(H^2\) |
The bar magnet \(A\) of magnetic moment \(M_A\) is found to oscillate at a frequency twice that of magnet \(B\) of magnetic moment \(M_B\) and the same moment of inertia when placed in a vibration magnetometer. We may say that:
| 1. | \(M_B=8M_A\) | 2. | \(M_A= 4M_B\) |
| 3. | \(M_A=8M_B\) | 4. | \(M_A=2M_B\) |
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