Q. No.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.
\(\dfrac{\sqrt{5}\mu_{0} M}{4\pi d^{3}}\)
A magnetic needle suspended by a silk thread is vibrating in the earth's magnetic field. If the temperature of the needle is increased, then:
| 1. | the time period decreases. |
| 2. | the time period remains unchanged. |
| 3. | the time period increases. |
| 4. | the time period first decreases then increases. |
For protecting a magnetic needle, it should be placed:
| 1. | In an iron box. |
| 2. | In a wooden box. |
| 3. | In a metallic box. |
| 4. | None of these. |
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. \(\mu_d= 0 ~\text{and}~\mu_p \ne0\)
Diamagnetic material in a magnetic field moves:
| 1. | from stronger to the weaker parts of the field |
| 2. | from weaker to the stronger parts of the field |
| 3. | perpendicular to the field |
| 4. | in none of the above directions |
Which of the following is the correct representation of magnetic field lines?
| 1. | (g), (c) | 2. | (d), (f) |
| 3. | (a), (b) | 4. | (c), (e) |
Which one of the following is correct?
| 1. | The magnetic field lines also represent the lines of force on a moving charged particle at every point. |
| 2. | Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid. |
| 3. | A bar magnet exerts a torque on itself due to its own field. |
| 4. | Magnetic field arises due to stationary charges. |
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. |
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