The following figures show the arrangement of bar magnet in different configurations. Each magnet has magnetic dipole moment m. Which configuration has the highest net magnetic dipole moment?
(i) (ii) (iii) (iv)

1. (i)

2. (ii)

3. (iii)

4. (iv)

A magnetic needle suspended parallel to a 

magnetic field requires $\sqrt{3}$ J of work to turn

it through $60°$. The torque needed to maintain 

the needle in this position will be

(1) $2\sqrt{3}$J                     

(2) 3 J

(3) $\sqrt{3}$ J                       

(4) $\frac{3}{2}$ J

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?

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 

1. zero

2. directed along OP

3. directed along PO

4. directed perpendicular to the plane of the paper

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

A bar magnet having a magnetic moment of $2\times {10}^4 J{T}^{-1}$ is free to rotate in a horizontal plane. A horizontal magnetic field $B=6\times {10}^{-4}T$ exists in the space. The work done in taking the magnet slowly from a direction parallel to the field to a direction $60°$ from the field is 

(a) 0.6 J                            (b) 12 J

(c) 6 J                               (d) 2 J

Curie temperature is the temperature above which -

1. ferromagnetic material becomes paramagnetic material 

2. paramagnetic material becomes diamagnetic material 

3. paramagnetic material becomes ferromagnetic material 

4. ferromagnetic material becomes diamagnetic material  

Domain formation is the necessary feature of : 

(1) ferromagnetism                   (2) diamagnetism

(3) paramagnetism                   (4) all of these

The magnetic susceptibility of a paramagnetic substance at -73$°$C is 0.0060, then its value at -173$°$C will be 

1. 0.0030

2. 0.0120

3. 0.0180

4. 0.0045

The magnetic dipoles in a diamagnetic material are represented, for three situations. The three situations differ in magnitude if a magnetic field is applied to the material. In which situation the magnetization of the material is the greatest: