A dip needle vibrates in the vertical plane perpendicular to the magnetic meridian. The time period of vibration is found to be 2 seconds. If the same needle is then allowed to vibrate in the horizontal plane and the time period is again found to be 2 seconds, then the angle of dip is:

1. 0^o

2. 30^o

3. 45^o

4. 90^o

If a bar magnet of magnetic moment M is freely suspended in a uniform magnetic field of strength B, the work done in rotating the magnet through an angle is

1. $MB(1-\sin \theta )$

2. $MB\sin \theta$

3. $MB\cos \theta$

4. $MB(1-\cos \theta )$

A magnet of magnetic moment $50\widehat{i } A-m^2$ is placed along the x-axis in a magnetic field $\overrightarrow{B}=(0.5\hat{i}+3.0\hat{j})T$. The torque acting on the magnet is:

1. 175 $\hat{k}$ N-m

2. 150 $\hat{k}$ N-m

3. 75 $\hat{k}$ N-m

4. 25$\sqrt{37}$ $\hat{k}$ N-m

The magnetic field lines due to a bar magnet are correctly shown in:

1.		2.
3.		4.

Among the following properties describing diamagnetism identify  the property that is wrongly stated

1. Diamagnetic material do not have permanent magnetic moment

2. Diamagnetism is explained in terms of electromagnetic induction

3. Diamagnetic materials have a small positive susceptibility

4. The magnetic moment of individual electrons neutralize each other

If the angular momentum of an electron is $\overrightarrow{J}$ then the magnitude of the magnetic moment will be

1. $\frac{eJ}{m}$                            2. $\frac{eJ}{2m}$

3. ej.2m                         4. $\frac{2m}{eJ}$

At a certain place, the horizontal component B₀ and the vertical component V₀ of the earth's magnetic field are equal in magnitude. The total intensity at the place will be

1. $B_0$                            2. $B_0^2$

3. $2B_0$                          4. $\sqrt{2}{B}_0$

If ${\varphi }_1$ and ${\varphi }_2$ be the angles of dip observed in two vertical planes at right angles to each other and $\varphi$ be the true angle of dip, then

1. ${\cos }^2\varphi ={\cos }^2{\varphi }_1+{\cos }^2{\varphi }_2$

2. ${\sec }^2\varphi ={\sec }^2{\varphi }_1+{\sec }^2{\varphi }_2$

3. ${\tan }^2\varphi ={\tan }^2{\varphi }_1+{\tan }^2{\varphi }_2$

4. ${\cot }^2\varphi ={\cot }^2{\varphi }_1+{\cot }^2{\varphi }_2$

The angle of dip at a certain place is 30^o. If the horizontal component of the earth’s magnetic field is H, the intensity of the total magnetic field is

1. $\frac{H}{2}$                            2. $\frac{2H}{\sqrt{3}}$

3. $H\sqrt{2}$                         4. $H\sqrt{3}$

Magnetic field lines

1. Cannot intersect

2. Are always closed curves

3. Can pass through vacuum

4. All of these