# MCQ Questions Chapter 5 Magnetism and Matter Class 12 Physics

Please refer to MCQ Questions Chapter 5 Magnetism and Matter Class 12 Physics with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 12 Physics issued for the current academic year. We have provided MCQ Questions for Class 12 Physics for all chapters on our website. Students should learn the objective based questions for Chapter 5 Magnetism and Matter in Class 12 Physics provided below to get more marks in exams.

## Chapter 5 Magnetism and Matter MCQ Questions

Please refer to the following Chapter 5 Magnetism and Matter MCQ Questions Class 12 Physics with solutions for all important topics in the chapter.

MCQ Questions Answers for Chapter 5 Magnetism and Matter Class 12 Physics

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

B

Question. Following figures show the arrangement of bar magnets in different configurations. Each magnet has magnetic dipole moment m¯ Which configuration has highest net magnetic dipole moment?

(a) (1)
(b) (2)
(c) (3)
(d) (4)

C

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. 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 of length ‘l’ and magnetic dipole moment ‘M’ is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be

(a) (2/π)M
(b) M/2
(c) M
(d) (3/π)M

D

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

A

Question. A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μA 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. 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. 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

(a) zero
(b) directed along OP
(c) directed along PO
(d) directed perpendicular to the plane of paper

A

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. 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. If θ1 and θ2 be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip θ is given by
(a) tan2θ = tan2θ1 + tan2θ2
(b) cot2θ = cot2θ1 – cot2θ2
(c) tan2θ = tan2θ1 – tan2θ2
(d) cot2θ = cot2θ1 + cot2θ

D

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 bar magnet of magnetic moment M¯, is placed in a magnetic field of induction B¯. The torque exerted on it is
(a) M¯ × B¯
(b) −M¯ B¯
(c) M¯ B
(d) −B¯x M¯

A, D

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. 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. 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. 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. 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. 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. 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 (μ0 = 4p × 10–7 T m A–1)
(a) 2.4π × 10–4 T m A–1
(b) 8.0 × 10–5 T m A–1
(c) 2.4π × 10–5 T m A–1
(d) 2.4π × 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 magnetic susceptibility is negative for
(a) ferromagnetic material only
(b) paramagnetic and ferromagnetic materials
(c) diamagnetic material only
(d) paramagnetic material only

C

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 moment of a diamagnetic atom is
(a) much greater than one
(b) 1
(c) between zero and one
(d) equal to zero

D

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

B

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

A

Question. For protecting a sensitive equipment from the external magnetic field, it should be
(a) surrounded with fine copper sheet
(b) placed inside an iron can
(c) wrapped with insulation around it when passing current through it
(d) placed inside an aluminium can

B

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

A

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. A diamagnetic material in a magnetic field moves
(a) from stronger to the weaker parts of the field
(b) from weaker to the stronger parts of the field
(c) perpendicular to the field
(d) in none of the above directions

A

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. 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

Assertion-Reason Questions

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R). Choose the correct answer out of the following choices.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Question. Assertion (A): The susceptibility of a diamagnetic substance is independent of temperature.
Reason (R): Every atom of a diamagnetic substance is characterised by electron pairs of opposite spin; so with change of temperature, the motion of electrons are affected by same amount in opposite directions.

A

Question. Assertion (A): For making permanent magnets, steel is preferred over soft iron.
Reason (R): As retentivity of steel is smaller.

B

Question. Assertion (A): If a compass needle be kept at magnetic north pole of Earth, the compass needle may stay in any direction.
Reason (R): Dip needle will stay vertical at the north pole of Earth.

B

Question. Assertion (A): Earth’s magnetic field does not affect the working of a moving coil galvanometer.
Reason (R): Earth’s magnetic field is very weak.

A

Question. Assertion (A): The poles of a magnet cannot be separated by breaking into two pieces.
Reason (R): The magnetic moment will be reduced to half when a magnet is broken into two equal pieces.

B

Question. Assertion (A): Diamagnetic materials can exhibit magnetism.
Reason (R): Diamagnetic materials have permanent magnetic dipole moment.

C

Question. Assertion (A): Gauss’s theorem is not applicable in magnetism.
Reason (R): Magnetic monopoles do not exist.

A

Question. Assertion (A): The ferromagnetic substances do not obey Curie’s law.
Reason (R): At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.

B

Question. Assertion (A): Soft iron is used a transformer core.
Reason (R): Soft iron has a narrow hysteresis loop.