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:

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 magnetic needle suspended parallel to a magnetic field requires \(\sqrt{3}~\text{J}\) of work to turn it through $\mathrm{}$\(60^\circ\). The torque needed to maintain the needle in this position will be:
1. \(3\) N-m
2. \(\sqrt{3} \) N-m
3. \(\frac32\) N-m
4. \(2\sqrt{3}\) N-m

A short bar magnet of magnet moment \(0.4\) ${\mathrm{JT}}^{-1}$ is placed in a uniform magnetic field of \(0.16\) $\mathrm{T}$. The magnet is in stable equilibrium when the potential energy is:
1. \(0.064\) J
2. \(-0.064\) J
3. zero
4.\(-0.082\) J

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 $\mu$T. When a horizontal field of 18 $\mu$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

The magnetic moment of a diamagnetic atom is:

1. 1

2. between zero and one

3. equal to zero

4. much greater than one