Points A and B are situated perpendicular to the axis of a 2cm long bar magnet at large distances X and 3X from its centre on opposite sides. The ratio of the magnetic fields at A and B will be approximately equal to
(a) 1 : 9               (b) 2 : 9
(c) 27 : 1             (d) 9 : 1

Concept Questions :-

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

Difficulty Level:

Two short magnets with their axes horizontal to the magnetic meridian are placed with their centres 40 cm east and 50 cm west of the magnetic needle. If the needle remains undeflected, the ratio of their magnetic moments  is

(a) 4:5

(b) 16:25

(c) 64:125

(D) 2:$\sqrt{5}$

Concept Questions :-

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

Difficulty Level:

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. $MB\left(1-\mathrm{sin}\theta \right)$

2. $MB\mathrm{sin}\theta$

3. $MB\mathrm{cos}\theta$

4. $MB\left(1-\mathrm{cos}\theta \right)$

Concept Questions :-

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

Difficulty Level:

Two small bar magnets are placed in a line with like poles facing each other at a certain distance d apart. If the length of each magnet is negligible as compared to d, the force between them will be inversely proportional to

(a) d

(b) d2

(c) $\frac{1}{{d}^{2}}$

(d) ${d}^{4}$

Concept Questions :-

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

Difficulty Level:

A magnet of magnetic moment M is situated with its axis along the direction of a magnetic field of strength B. The work done in rotating it by an angle of 180o will be

(a) -MB                         (b) +MB

(c) 0                             (d) +2MB

Concept Questions :-

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

Difficulty Level:

A magnetic needle is kept in a non-uniform magnetic field. It experiences

1. A force and a torque

2. A force but not a torque

3. A torque but not a force

4. Neither a torque nor a force

Concept Questions :-

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

Difficulty Level:

A long magnetic needle of length 2L, magnetic moment M and pole strength m units is broken into two pieces at the middle. The magnetic moment and pole strength of each piece will be

1. $\frac{M}{2},\frac{m}{2}$

2. $M,\frac{m}{2}$

3. $\frac{M}{2},m$

4. M, m

Concept Questions :-

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

Difficulty Level:

Two identical thin bar magnets each of length l and pole strength m are placed at the right angle to each other with the north pole of one touching south pole of the other. The magnetic moment of the system is :

1. ml

2. 2ml

3. $\sqrt{2}ml$

4. $\frac{1}{2}ml$

Concept Questions :-

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

Difficulty Level:

Rate of change of torque  with deflections maximum for a magnet suspended freely in a uniform magnetic field of induction B, when

(a) $\theta ={0}^{o}$                        (b) $\theta ={45}^{o}$

(c) $\theta ={60}^{o}$                      (d) $\theta ={90}^{o}$

Concept Questions :-

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

Difficulty Level:

Force between two identical bar magnets whose centres are r metre apart  is 4.8 N, when their axes are in the same line. If separation is increased to 2r, the force between them is reduced to

1. 2.4N                         2. 1.2N

3. 0.6N                         4. 0.3N

Concept Questions :-

Analogy between electrostatics and magnetostatics