A substance is placed in an external magnetic field. If the direction of induced dipole moment is opposite to the direction of the applied magnetic field, then the substance may be

1. Paramagnetic

2. Diamagnetic

3. Ferromagnetic

4. Both (1) & (3)

If B_o is magnetic flux density in vacuum produced by a magnetising force and magnetic flux density produced by the magnetisation of a material due to the same magnetising force is B_m, then the total magnetic flux density in the material is :

$1. B_{\circ }+ B_m$
$2. B_{\circ }- B_m$
$3. \frac{B_{\circ }}{B_m}$
$4. \frac{B_m}{B_{\circ }}$
$$

Which of the following graphs represents the correct variation of the intensity of magnetisation (I) with the intensity of the magnetising field (H) in a ferromagnetic substance?

1.		2.
3.		4.

The magnetic susceptibility of a substance is -0.0002 at room temperature. If this substance is kept in a uniform external magnetic field B, the net field inside the substance becomes B', then :

1. B'$>$B

2. B'$<$B

3. B' = B

4. B' = 0

The magnetic moment of a short dipole is \(100\) A-m². The magnetic induction in vacuum at \(1\) m from the dipole on the axis of the dipole is:

The magnetic moment of a magnet \((10 ~\text{cm}\times 4~\text{cm}\times1~\text{cm})\) is \(4 ~\text{Am}^2\). Its intensity of magnetisation is:
1. \(10^{3}\) A/m
2. \(10^{2}\) A/m
3. \(10^{5}\) A/m
4. \(10^{4}\) A/m

S.I. unit of intensity of magnetization is:

A ferromagnetic material is placed in an external magnetic field. The magnetic domains:

If a magnetic dipole of dipole moment $\mu$ is rotated through an angle $\theta$ with respect to the direction of the magnetic field B, then work done is :

1. $\mu$Bsin$\theta$

2. $\mu$B(1-sin$\theta$)

3. $\mu$Bcos$\theta$

4. $\mu$B(1-cos$\theta$)

Magnetic permeability is maximum for

1. Diamagnetic substance

2. Paramagnetic substance

3. Ferromagnetic substance

4. Same for all three substances