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 in-
1. direction along OP
2. direction along PQ
3. direction perpendicular to the plane of paper
4. zero

The magnetic moment of a diamagnetic atom is

1. 1

2. between zero and one

3. equal to zero

4. much greater than one

A short bar magnet of magnet moment 0.4 ${\mathrm{JT}}^{-1}$ is placed in a uniform magnetic field of 0.16 $\mathrm{T}$. The magnet is in stable equilibrium when the potential energy is :
1. 0.064 J
2. – 0.064 J
3. Zero
4. – 0.082 J

A magnetic needle suspended parallel to a magnetic field requires $\sqrt{3}$ J of work to turn it through $60°$. The torque needed to maintain the needle in this position will be:

1.  3 J 

2. $\sqrt{3} J$

3.  $\frac{3}{2}J$

4. $2\sqrt{3} J$

Above Curie temperature:

1. a ferromagnetic substance becomes paramagnetic.

2. a paramagnetic substance becomes diamagnetic.

3. a diamagnetic substance becomes paramagnetic.

4. a paramagnetic substance becomes ferromagnetic.

Nickel shows the ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show:

1. paramagnetism

2. anti-ferromagnetism

3. no magnetic property

4. diamagnetism

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

1. Repelled by both the poles

2. Repelled by the north pole and
    attracted by the south pole

3. Attracted by the north pole and
    repelled by the south pole

4. Attracted by both the poles

Electromagnets are made of soft iron because soft iron has:

1. low retentivity and high coercive force

2. high retentivity and high coercive force

3. low retentivity and low coercive force

4. high retentivity and low coercive force