# MCQs For NCERT Class 12 Physics Chapter 5 Magnetism and Matter

Please refer to the MCQ Questions for Class 12 Physics Chapter 5 Magnetism and Matter with Answers. The following Magnetism and Matter Class 12 Physics MCQ Questions have been designed based on the latest syllabus and examination pattern for Class 12. Our experts have designed MCQ Questions for Class 12 Physics with Answers for all chapters in your NCERT Class 12 Physics book.

## Magnetism and Matter Class 12 MCQ Questions with Answers

See below Magnetism and Matter Class 12 Physics MCQ Questions, solve the questions and compare your answers with the solutions provided below.

Question. Magnetic lines of force due to a bar magnet do not intersect because
(a) a point always has a single net magnetic field
(b) the lines have similar charges and so repel each other
(c) the lines always diverge from a single force
(d) the lines need magnetic lenses to be made to interest

A

Question. A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 mA and subjected to a magnetic field of strength 0.85 T.
Work done for rotating the coil by 180° against the torque is
(a) 4.55 mJ
(b) 2.3 mJ
(c) 1.15 mJ
(d) 9.1 mJ

D

Question. If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is
(a) repelled by the north pole and attracted by the south pole
(b) attracted by the north pole and repelled by the south pole
(c) attracted by both the poles
(d) repelled by both the poles

D

Question. The magnetic susceptibility of an ideal diamagnetic substance is
(a) –1
(b) 0
(c) +1
(d) ¥

A

Question. If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by md, mp and mf respectively, then
(a) md = 0 and mp ≠ 0
(b) md ≠ 0 and mp = 0
(c) mp = 0 and mf ≠ 0
(d) md ≠ 0 and mf ≠ 0.

A

Question. A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by 60° is W. Now the torque required to keep the magnet in this new position is
(a) W√3
(b) 3W
(c) √3W /2
(d) 2W/3

B

Question. A magnetic needle suspended parallel to a magnetic field requires 3 J of work to turn it through 60°.
The torque needed to maintain the needle in this position will be
(a) 2√3J
(b) 3 J
(c) √3 J
(d) 3/2 J

B

Question. A short bar magnet of magnetic moment 0.4 J T–1 is placed in a uniform magnetic field of 0.16 T. The magnet is in stable equilibrium when the potential energy is
(a) 0.064 J
(b) –0.064 J
(c) zero
(d) –0.082 J

B

Question. If q1 and q2 be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip q is given by
(a) tan2q = tan2q1 + tan2q2
(b) cot2q = cot2q1 – cot2q2
(c) tan2q = tan2q1 – tan2q2
(d) cot2q = cot2q1 + cot2q2

D

Question. Two points A and B are situated at a distance x and 2x respectively from the nearer pole of a magnet 2 cm long. The ratio of magnetic field at A and B is
(a) 4 : 1 exactly
(b) 4 : 1 approximately
(c) 8 : 1 approximately
(d) 1 : 1 approximately

C

Question. Imagine rolling a sheet of paper into a cylinder and placing a bar magnet near its end as shown in figure. What can you say about the sign of B.dA for every area dA on the surface?
(a) Positive
(b) Negative
(c) No sign
(d) Can be positive or negative

B

Question. A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 sec in earth’s horizontal magnetic field of 24 microtesla.
When a horizontal field of 18 microtesla is produced opposite to the earth’s field by placing a current carrying wire, the new time period of magnet will be
(a) 1 s
(b) 2 s
(c) 3 s
(d) 4 s

D

Question. A bar magnet having a magnetic moment of 2 × 104 J T–1 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) 12 J
(b) 6 J
(c) 2 J
(d) 0.6 J

B

Question. According to Curie’s law, the magnetic susceptibility of a substance at an absolute temperature T is proportional to
(a) 1/T
(b) T
(c) 1/T2
(d) T2

A

Question. Among which the magnetic susceptibility does not depend on the temperature?
(a) Diamagnetism
(b) Paramagnetism
(c) Ferromagnetism
(d) Ferrite.

A

Question. Curie temperature above which
(a) paramagnetic material becomes ferromagnetic material
(b) ferromagnetic material becomes diamagnetic material
(c) ferromagnetic material becomes paramagnetic material
(d) paramagnetic material becomes diamagnetic material

C

Question. A closely wound solenoid of 2000 turns and area of cross-section 1.5 × 10–4 m2 carries a current of 2.0 A.
It is suspended through its centre and perpendicular to its length, allowing it to turn in a horizontal plane in a uniform magnetic field 5 × 10–2 tesla making an angle of 30° with the axis of the solenoid.
The torque on the solenoid will be
(a) 3 × 10–3 N m
(b) 1.5 × 10–3 N m
(c) 1.5 × 10–2 N m
(d) 3 × 10–2 N m

C

Question. Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show
(a) anti ferromagnetism
(b) no magnetic property
(c) diamagnetism
(d) paramagnetism.

D

Question. Which one of the following statement is not correct about the magnetic field ?
(a) Inside the magnet the lines go from north pole to south pole of the magnet
(b) Tangents to the magnetic lines give the direction of the magnetic field
(c) The magnetic lines form a closed loop
(d) Magnetic lines of force do not cut each other

A

Question. A bar magnet is oscillating in the Earth’s magnetic field with a period T. What happens to its period and motion if its mass is quadrupled ?
(a) Motion remains simple harmonic with time period = T/2
(b) Motion remains S.H.M with time period = 2T
(c) Motion remains S.H.M with time period = 4T
(d) Motion remains S.H.M and period remains nearly constant

B

Question. Liquid oxygen remains suspended between two pole forces of a magnet because it is :
(a) diamagnetic
(b) paramagnetic
(c) ferromagnetic
(d) antiferromagnetic

B

Question. Two bar magnets having same geometry with magnetic moments M and 2M, are firstly placed in such a way that their similar poles are in same side then its time period of oscillation is T1. Now the polarity of one of the magnet is reversed then time period of oscillation is T2, then
(a) T1 < T2
(b) T1 = T2
(c) T1 > T2
(d) T2 = ∞

A

Question. A frog can be levitated in a magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as :
(a) paramagnetic
(b) diamagnetic
(c) ferromagnetic
(d) antiferromagnetic

C

Question. A bar magnet of magnetic moment M is cut into two parts of equal length. The magnetic moment of each part will be
(a) M
(b) 2M
(c) zero
(d) 0.5M

D

Question. The best material for the core of a transformer is
(a) mild steel
(b) stainless steel
(c) soft iron
(d) hard steel

C

Question. The work done in turning a magnet of magnetic moment M by an angle of 90° from the meridian, is n times the corresponding work done to turn it through an angle of 60°. The value of n is given by
(a) 1/2
(b) 1/4
(c) 2
(d) 1

C

Question. Which one of the following are used to express intensity of magnetic field in vacuum ?
(a) oersted
(b) tesla
(c) gauss
(d) none of these

A

Question. At a point A on the earth’s surface the angle of dip, d = +25°. At a point B on the earth’s surface the angle of dip, d = –25°. We can interpret that (a) A and B are both located in the southern hemisphere.
(b) A and B are both located in the northern hemisphere.
(c) A is located in the southern hemisphere and B is located in the northern hemisphere.
(d) A is located in the northern hemisphere and B is located in the southern hemisphere.

D

Question. A magnet 10 cm long and having a pole strength 2 amp m is deflected through 30° from the magnetic meridian. The horizontal component of earth’s induction is 0.32´10-4 tesla then the value of deflecting couple is:
(a) 32 ´10-7Nm
(b) 16 ´10-7Nm
(c) 64 ´10-7Nm
(d) 48 ´10-7Nm

A

Question. A bar magnet of magnetic moment M is placed at right angles to a magnetic induction B. If a force F is experienced by each pole of the magnet, the length of the magnet will be
(a) MB/F
(b) BF/M
(c) MF/B
(d) F/MB

C

Question. Angle of dip is 90° at:
(a) Equator
(b) Middle point
(c) Poles
(d) None of these

C

Question. A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It
(a) will become rigid showing no movement
(b) will stay in any position
(c) will stay in north-south direction only
(d) will stay in east-west direction only

B

Question. Tangent galvanometer is used to measure
(a) potential difference
(b) current
(c) resistance
(d) charge.

B

Question. Curie temperature is the temperature above which
(a) a ferromagnetic material becomes paramagnetic
(b) a paramagnetic material becomes diamagnetic
(c) a ferromagnetic material becomes diamagnetic
(d) a paramagnetic material becomes ferromagnetic

A

Question. An iron rod of susceptibility 599 is subjected to a magnetising field of 1200 A m–1. The permeability of the material of the rod is (m0 = 4p × 10–7 T m A–1)
(a) 2.4p × 10–4 T m A–1
(b) 8.0 × 10–5 T m A–1
(c) 2.4p × 10–5 T m A–1
(d) 2.4p × 10–7 T m A–1

A

Question. A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy.
The work required to do this comes from
(a) the current source
(b) the magnetic field
(c) the lattice structure of the material of the rod
(d) the induced electric field due to the changing magnetic field

A

Question. The north pole of a magnet is brought near a metallic ring. Then the direction of the induced current in the ring will be:
(a) Towards north
(b) Towards south
(c) Anticlockwise
(d) Clockwise

C

Question. 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

C

Question. A bar magnet is oscillating in the Earth’s magnetic field with a period T. What happens to its period and motion if its mass is quadrupled?
(a) Motion remains S.H. and period remains nearly constant
(b) Motion remains S.H. with time period = T/2
(c) Motion remains S.H. with time period = 2T
(d) Motion remains S.H. with time period = 4T

C

Question. The magnet of pole strength m and magnetic moment M is cut into two pieces along its axis. Its pole strength and magnetic moment now becomes

A

Question. If a diamagnetic substance is brought near north or south pole of a bar magnet, it is
(a) attracted by the poles
(b) repelled by the poles
(c) repelled by north pole and attracted by the south pole
(d) attracted by the north pole and repelled by the south pole

B

Question. 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 ?
(a) B is of a paramagnetic material
(b) C is of a diamagnetic material
(c) D is of a ferromagnetic material
(d) A is of a non-magnetic material

A

Question. A diamagnetic material in a magnetic field moves
(a) perpendicular to the field
(b) from stronger to the weaker parts of the field
(c) from weaker to the stronger parts of the field
(d) None of these

B

Question. A bar magnet of magnetic moment M and length L is cut into two equal parts each of length L/2. The magnetic moment of each part will be
(a) M
(b) M/4
(c) √2M
(d) M/2

D

Question. Two magnets of magnetic moments M and 2M are placed in a vibration magnetometer, with the identical poles in the same direction. The time period of vibration is T1. If the magnets are placed with opposite poles together and vibrate with time period T2, then
(a) T2 is infinite
(b) T2 = T1
(c) T2 > T1
(d) T2 < T1

C

Question. Two tangent galvanometers having coils of the same radius are connected in series. A current flowing in them produces deflections of 60º and 45º respectively. The ratio of the number of turns in the coils is

D

Question. A curve between magnetic moment and temperature of magnet is

C

Question. The B – H curve (i) and (ii) shown in fig. associated with

(a) (i) diamagnetic and (ii) paramagnetic substance
(b) (i) paramagnetic and (ii) ferromagnetic substance
(c) (i) soft iron and (ii) steel respectively
(d) (i) steel and (ii) soft iron respectively

A

Question. At a temperatur of 30°C, the susceptibility of a ferromagnetic material is found to be c . Its susceptibility at 333°C is
(a) c
(b) 0.5 c
(c) 2c
(d) 11.1c