1. | paramagnetic material only. |
2. | ferromagnetic material only. |
3. | paramagnetic and ferromagnetic materials. |
4. | diamagnetic material only. |
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. | \(\dfrac{3M}{\pi}\) | 2. | \(\dfrac{2M}{l\pi}\) |
3. | \(\dfrac{M}{ 2}\) | 4. | \(M\) |
A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It:
1. will become rigid showing no movement
2. will stay in any position
3. will stay in north-south direction only
4. will stay in east-west direction only
(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
Electromagnets are made of soft iron because soft iron has:
1. low retentivity and high coercive force
2. high retentivity and high coercive force
3. low retentivity and low coercive force
4. high retentivity and low coercive force
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 |