A bar magnet has coercivity \(4\times 10^{3}~\text{Am}^{-1}\). It is desired to demagnetize it by inserting it inside a solenoid \(12~\text{cm}\) long and having \(60\) turns. The current that should be sent through the solenoid is:
1. \(2\) A
2. \(4\) A
3. \(6\) A
4. \(8\) A

A uniform magnetic field, parallel to the plane of the paper existed in space initially directed from left to right. When a bar of soft iron is placed in the field parallel to it, the lines of force passing through it will be represented by:

1.		2.
3.		4.

A dip needle vibrates in the vertical plane perpendicular to the magnetic meridian. The time period of vibration is found to be 2 seconds. If the same needle is then allowed to vibrate in the horizontal plane and the time period is again found to be 2 seconds, then the angle of dip is:

1. 0^o

2. 30^o

3. 45^o

4. 90^o

A dip needle in a plane perpendicular to magnetic meridian will remain:
1. Vertical
2. Horizontal
3. In any direction
4. At an angle of dip to the horizontal

The earth's magnetic field at a certain place has a horizontal component 0.3 Gauss and the total strength 0.5 Gauss. The angle of dip is:

1. ${\tan }^{-1}\left(\frac{3}{4}\right)$                     

2. ${\sin }^{-1}\left(\frac{3}{4}\right)$

3. ${\tan }^{-1}\left(\frac{4}{3}\right)$                     

4. ${\sin }^{-1}\left(\frac{3}{5}\right)$

A superconductor exhibits perfect:
1. Ferrimagnetism
2. Ferromagnetism
3. Paramagnetism             
4. Diamagnetism

Two short magnets of equal dipole moments \(M\) are fastened perpendicularly at their centres (figure). The magnitude of the magnetic field at a distance \(d\) from the centre on the bisector of the right angle is:

The variation of magnetic susceptibility $\left(\chi \right)$ with temperature for a diamagnetic substance is best represented by:

1.		2.
3.		4.

The variation of the intensity of magnetisation \((I)\) with respect to the magnetising field \((H)\) in a diamagnetic substance is described by the graph:

There are four light-weight-rod samples; A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted:

Which one of the following is true?