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.
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 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
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. |