Which of the following is the correct representation of magnetic field lines?

| 1. | (g), (c) | 2. | (d), (f) |
| 3. | (a), (b) | 4. | (c), (e) |
If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by \(\mu_d,~\mu_p,~\text{and}~\mu_f\) respectively, then:
1. \(\mu_p= 0 ~\text{and}~\mu_f \ne0\)
2. \(\mu_d\neq 0 ~\text{and}~\mu_p=0\)
3. \(\mu_d\ne 0 ~\text{and}~\mu_f \ne0\)
4. \(\mu_d= 0 ~\text{and}~\mu_p \ne0\)
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. | \(\dfrac{2 \mu_{0} M}{4 \pi d^{3}}\) | 2. | \(\dfrac{\mu_{0} M}{4 \pi d^{3}}\) |
| 3. | zero | 4. | \(\dfrac{\sqrt{5}\mu_{0} M}{4\pi d^{3}}\) |
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. |
| 1. | \(9~\text{gauss}\) | 2. | \(4~\text{gauss}\) |
| 3. | \(36~\text{gauss}\) | 4. | \(4.5~\text{gauss}\) |
The magnetic moment of a magnet \((10 ~\text{cm}\times 4~\text{cm}\times1~\text{cm})\) is \(4 ~\text{Am}^2\). Its intensity of magnetisation is:
1. \(10^{3}~\text{A/m}\)
2. \(10^{2}~\text{A/m}\)
3. \(10^{5}~\text{A/m}\)
4. \(10^{4}~\text{A/m}\)
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 |