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:
            

An iron rod of length L and magnetic moment M is bent in the form of a semicircle. Now its magnetic moment will be 

1. M

2. $\frac{2\mathrm{M}}{\mathrm{\pi }}$

3. $\frac{\mathrm{M}}{\mathrm{\pi }}$

4. $\mathrm{M\pi }$

Time period of a freely suspended magnet does not depend upon 

1. length of the magnet

2. pole strength of the magnet

3. horizontal component of earth's magentic field

4. length of the suspension thread

Relative permeability of iron is 5500, then its magnetic suceptibility will be -

1. 5501

2. 5499

3. $5500\times {10}^7$

4. none of these