Q. No.Magnetic induction at an axial point of a short magnet at a distance \(r\) from the centre of dipole is \(\vec B\). Its value at the equatorial point of the short magnet at the same distance from the centre of dipole is:
1.
\(-\vec B\)
2.
\(\dfrac{\vec B}{2}\)
3.
\(\vec B\)
4.
\(\dfrac{-\vec B}{2}\)
Consider a magnetic dipole kept in the east-west direction. Let P1, P2, Q1, Q2 be four points at the same distance from the dipole towards north, south, east and west of the dipole respectively. The directions of the magnetic field due to the dipole are the same only at:
1. P1 and Q1
2. P2 and Q1
3. P1 and Q2
4. Q1 and Q2
The magnetic moment of a bar magnet of length \(L\) and area of cross-section \(A\) is \(M\). If the magnet is cut into four identical parts each of length \(L\) and area of cross-section \(\frac{A}{4}\), then magnetic moment of each part is:
| 1. | \(\frac{M}{4}\) | 2. | \(\frac{M}{2}\) |
| 3. | \(M\) | 4. | \(4M\) |
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 apparent dip at a place is always greater than or equal to the value of true dip at that place. This is due to
1. An increase in the apparent value of BV
2. A decrease in the apparent value of BH
3. An increase in the apparent value of BH
4. Both (1) & (2)
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 |
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. |
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. |
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
Elements of Earth's magnetism is/are
1. Magnetic declination
2. Magnetic Inclination (or dip)
3. The horizontal component of the earth's magnetic field
4. All of these
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