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 :

$1.<mspace\; width="1em"></mspace>B_{\circ }+<mspace\; width="1em"></mspace>B_m$
$2.<mspace\; width="1em"></mspace>B_{\circ }-<mspace\; width="1em"></mspace>B_m$
$3.<mspace\; width="1em"></mspace>\frac{B_{\circ }}{B_m}$
$4.<mspace\; width="1em"></mspace>\frac{B_m}{B_{\circ }}$
$$

A magnet (primary) oscillates with frequency ${\mathrm{\nu }}_1$ in earth's magnetic field (B_H) alone. Now a secondary magnet is placed near the primary magnet. If B is the magnetic field of the second magnet on the primary magnet in the direction of B_H, the primary magnet oscillates with frequency ${\mathrm{\nu }}_2$, then the ratio of B/B_H is :

1. ${\left(\frac{{\mathrm{\nu }}_2}{{\mathrm{\nu }}_1}\right)}^2$

2. ${\left(\frac{v_2}{v_1}\right)}^2$-1

3. ${\left(\frac{{\mathrm{\nu }}_2}{{\mathrm{\nu }}_1}\right)}^2$ + 1

4. ${\left(\frac{{\mathrm{\nu }}_1}{{\mathrm{\nu }}_2}\right)}^2$-1

The angle of dip is ${\theta }_1$ on a given meridian which is at an angle $\theta$ with the magnetic meridian. If ${\theta }_2$ is the angle of dip on another meridian which is perpendicular to the first meridian, then $\mathrm{\theta },<mspace\; width="1em"></mspace>{\mathrm{\theta }}_{1<mspace\; width="1em"></mspace>}\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{\theta }}_2$ are related as :

1. cot²$\theta$ = cot²${\theta }_1$+cot²${\theta }_2$

2. tan²$\theta$ = tan²${\theta }_1$+tan²${\theta }_2$

3. tan$\theta$ = $\frac{\tan {\theta }_1}{\tan {\theta }_2}$

4. tan$\theta$ = tan${\theta }_1$ + tan${\theta }_2$

The magnetic susceptibility χ of a ferromagnetic material varies with temperature, as:

1.		2.
3.		4.

Which of the following is not dimensionless?
(where symbols stand for their usual meanings in magnetism)
1. \(\frac{I}{H}\)
2. \(\frac{B}{\mu_0H}\)
3. \(\mu_r\)
4. \(\frac{\mu_r B}{H}\)

The unit of intensity of the magnetising field is :

1.$\frac{N}{Wb}$

2. $\frac{J}{m^3\times tesla}$

3. $\frac{J}{m\times Wb}$

4. All of these

If at any place, the angle of dip is  $\theta$ and magnetic latitude is $\lambda$, then (assume that the axis of earth's magnetic moment coincides with axis of rotation of the earth)

1. $\theta$ =  $\lambda$

2. tan$\theta$ = cos$\lambda$

3. tan$\theta$.cot$\lambda$ = 2

4. tan$\theta$.cot$\lambda$ =$\frac{1}{2}$

If A is the area of the graph of the intensity of magnetisation in ferromagnetic material versus magnetising field intensity, V is the volume of the magnetic sample and n is the frequency of alternating magnetic field, then the rate of hysteresis loss in the substance is 

1. A

2. AVn

3. $\frac{AV}{n}$

4. $\frac{A}{nV}$

A magnet is oscillating with the time period 'T' in a vertical plane. If the angle of dip at that place is 60$°$ and the magnet is restricted to oscillate in the horizontal plane, then the time period of oscillations will be :

1. T

2. $\frac{T}{\sqrt{2}}$

3. $\sqrt{2}T$

4. 2T