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 magnetic needle suspended parallel to a magnetic field requires $\sqrt{3}~\text{J}$ of work to turn it through $60^\circ$. 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

The magnetic moment of a diamagnetic atom is:

1. 1

2. between zero and one

3. equal to zero

4. much greater than one

Two identical bar magnets are fixed with their centres at a distance $d$ apart. A stationary charge $Q$ is placed at $P$ in between the gap of the two magnets at a distance $D$ from the centre $O$ as shown in the figure:

The force on the charge $Q$ is in:

If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is: