Figure shows two small identical magnetic dipoles a and b of magnetic moments M each, placed at a separation 2d, with their axes perpendicular to each other. The magnetic field at the point P midway between the dipoles is:
1.
2.
3. Zero
4.
If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by µd, µp, and µf respectively, then:
1. µp = 0 and µf ≠ 0
2. µd ≠ 0 and µp = 0
3. µd ≠ 0 and µf ≠ 0
4. µd = 0 and µp ≠ 0
Which of the following is the correct representation of magnetic field lines?
1. (g), (c)
2. (d), (f)
3. (a), (b)
4. (c), (e)
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. |
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. |
Due to a small magnet, the intensity at a distance \(x\) in the end-on position is \(9~\text{gauss}\). What will be the intensity at a distance \(\frac{x}{2}\) on equatorial position?
1. \(9~\text{gauss}\)
2. \(4~\text{gauss}\)
3. \(36~\text{gauss}\)
4. \(4.5~\text{gauss}\)
The magnetic moment of a magnet \((10 ~cm\times 4~cm\times1~cm)\) is \(4 ~Am^2\). Its intensity of magnetisation is:
1. 103 A/m
2. 102 A/m
3. 105 A/m
4. 104 A/m
The material which is used to make permanent magnet has:
1. | High retentivity, low coercivity |
2. | Low retentivity, low coercivity |
3. | Low retentivity, high coercivity |
4. | High retentivity, high coercivity |
There are four light-weight-rod samples; A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted:
i. | A is feebly repelled |
ii. | B is feebly attracted |
iii. | C is strongly attracted |
iv. | D remains unaffected |
Which one of the following is true?
1. | C is of a diamagnetic material |
2. | D is of a ferromagnetic material |
3. | A is of a non-magnetic material |
4. | B is of a paramagnetic material |