The following figures show the arrangement of bar magnets in different configurations. Each magnet has a magnetic dipole. Which configuration has the highest net magnetic dipole moment?
1. | 2. | ||
3. | 4. |
A bar magnet of length \(‘l’\) and magnetic dipole moment \(‘M’\) is bent in the form of an arc as shown in the figure. The new magnetic dipole moment will be:
1. | \(3M/ \pi\) | 2. | \(2M/ l\pi\) |
3. | \(M/ 2\) | 4. | \(M\) |
i. | \(A\) is feebly repelled. |
ii. | \(B\) is feebly attracted. |
iii. | \(C\) is strongly attracted. |
iv. | \(D\) remains unaffected. |
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. |
A vibration magnetometer placed in a magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 s in the earth's horizontal magnetic field of 24 T. When a horizontal field of 18 T is produced opposite to the earth's field by placing a current-carrying wire, the new time period of the magnet will be:
1. 1 s
2. 2 s
3. 3 s
4. 4 s
If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is:
1. | repelled by both the poles |
2. | repelled by the north pole and attracted by the south pole |
3. | attracted by the north pole and repelled by the south pole |
4. | attracted by both the poles |
Nickel shows the ferromagnetic property at room temperature. If the temperature is increased beyond Curie's temperature, then it will show:
1. paramagnetism
2. anti-ferromagnetism
3. no magnetic property
4. diamagnetism
1. | paramagnetic material only |
2. | ferromagnetic material only |
3. | paramagnetic and ferromagnetic materials |
4. | diamagnetic material only |
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from:
1. | the current source |
2. | the magnetic field |
3. | the lattice structure of the material of the rod |
4. | the induced electric field due to the changing magnetic field. |
A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in the equilibrium state. The energy required to rotate it by 60o is W. Now the torque required to keep the magnet in this new position is:
1.
2.
3.
4.