A current carrying coil is placed with its axis perpendicular to N-S direction. Let horizontal component of earth's magnetic field be ${\mathrm{H}}_0$ and magnetic field inside the loop be H. If a magnet is suspended inside the loop, it makes angle $\mathrm{\theta }$ with H. Then $\mathrm{\theta }$=

1. ${\tan }^{-1}\left(\frac{H_0}{H}\right)$

2. ${\tan }^{-1}\left(\frac{H}{H_{\mathit{0}}}\right)$

3. $\cos e{c}^{-1}\left(\frac{H}{H_{\mathit{0}}}\right)$

4. $co{t}^{-1}\left(\frac{H_0}{H}\right)$

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

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

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. $\mathrm{M\pi }$

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:
            

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

Domain formation is the necessary feature of : 

(1) ferromagnetism                   (2) diamagnetism

(3) paramagnetism                   (4) all of these

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  

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

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