A vibration magnetometer placed in a magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2s in earth's horizontal magnetic field of 24 $\mu$T. When a horizontal field is 18 $\mu$T is produced opposite to the earth's field by placing a current-carrying wire, the new time period of the magnet will be

(a) 1s          (b) 2s

(c) 3s          (d) 4s

Concept Questions :-

Bar magnet
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Difficulty Level:

Electromagnets are made of soft iron because soft iron has :

(a) low retentivity and high coercive force

(b) high retentivity and high coercive force

(c) low retentivity and low coercive force

(d) high retentivity and low coercive force

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Difficulty Level:

The magnetic moment of a diamagnetic atom is

(a) much greater than one

(b) one

(c) between zero and one

(d) equal to zero

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Difficulty Level:

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

1. zero

2. directed along OP

3. directed along PO

4. directed perpendicular to the plane of the paper

Concept Questions :-

Bar magnet
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

Concept Questions :-

Magnetic materials
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A bar magnet having a magnetic moment of  is free to rotate in a horizontal plane. A horizontal magnetic field $B=6×{10}^{-4}T$ 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

Concept Questions :-

Bar magnet
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Curie temperature is the temperature above which -

(a) ferromagnetic material becomes paramagnetic material

(b) paramagnetic material becomes diamagnetic material

(d) paramagnetic material becomes ferromagnetic material

(d) ferromagnetic material becomes diamagnetic material

Concept Questions :-

Magnetic materials
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Difficulty Level:

A short bar magnet of magnetic moment  is placed in a uniform magnetic field of  The magnet is stable equilibrium when the potential energy is

(a)                                          (b) zero

(c)                                         (d)

Concept Questions :-

Bar magnet
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There are four light-weight-rod samples; A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted:

(i) A is feebly repelled

(ii) B is feebly attracted

(iii) C is strongly attracted

(iv) D remains unaffected

Which one of the following is true?

1. C is of a diamagnetic material

2. D is of a ferromagnetic material

3. A is of a non-magnetic material

4. B is of a paramagnetic material

Concept Questions :-

Magnetic materials
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

(a) $2\sqrt{3}$J                      (b) 3 J

(c) $\sqrt{3}$ J                       (d) $\frac{3}{2}$ J

Concept Questions :-

Bar magnet