The following figures show the arrangement of bar magnets in different configurations. Each magnet has 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. 3M/$\mathrm{\pi }$
2. 2M/l$\mathrm{\pi }$
3. M/2
4. M

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

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-
1. direction along OP
2. direction along PQ
3. direction perpendicular to the plane of paper
4. zero

A bar magnet is oscillating in the Earth's magnetic field with a period T. What happens to this period and motion if this mass is quadrupled:

Two bar magnets having the same geometry with magnetic moments M and 2M, are firstly placed in such a way that if their similar poles are on the same side then its time period of oscillation is T₁. Now if the polarity of one of the magnets is reversed then the time period of oscillation is T_2. The relation between T₁ & T₂ is:

1. ${\mathrm{T}}_1<{\mathrm{T}}_2$

2. ${\mathrm{T}}_1={\mathrm{T}}_2$

3. ${\mathrm{T}}_1>{\mathrm{T}}_2$

4. ${\mathrm{T}}_2=\infty$

For a vibration magnetometer, the time period of the suspended bar magnet can be reduced by:

1.  moving it towards the south pole
2.  moving it towards the north pole
3.  moving it towards the equator
4.  anyone of them