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
Above Curie temperature:
1. a ferromagnetic substance becomes paramagnetic.
2. a paramagnetic substance becomes diamagnetic.
3. a diamagnetic substance becomes paramagnetic.
4. a paramagnetic substance becomes ferromagnetic.
At point A on the earth's surface, the angle of dip is, . At a point B on the earth's surface, the angle of dip is, . We can interpret that:
1. | A and B are both located in the southern hemisphere. |
2. | A and B are both located in the northern hemisphere. |
3. | A is located in the southern hemisphere and B is located in the northern hemisphere. |
4. | A is located in the northern hemisphere and B is located in the southern hemisphere. |
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
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
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. | \(M\) |
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. |