CBSE Class 12 Chapter 5 Magnetism and Matter

CBSE Class 12 Chapter 5 MCQs: CBSE Class 12 Chapter 5 Magnetism and Matter is one of the most intresting and conceptual chapters in the CBSE Class 12 Physics Syllabus. This topic helps students understand how magnetic field works in nature and inside materials. From Earth’s magnetism to magnetic dipole moment and bar magnet, everything is explained step by step in simple way. The chapter also covers important laws like Gauss’s law in magnetism and magnetic properties of substances which are very helpful for board exams and competitive tests.

Students can prepare MCQs on Class 12 Chapter 5 Magnetism and Matter to improve their understanding and boost confidence. Regular practice from magnetism and matter class 12 mcq and physics class 12 mcq chapter 5 helps to revise key formulas and concepts faster. Many MCQs questions in CBSE Class 12 Board exams are directly based on NCERT Solutions for Class 12 Physics, so reading line by line is very useful.

CBSE Class 12 Physics - Chapter 5 Magnetism and Matter

1. The earth’s magnetic field is due to

A. Presence of magnetic materials in earth

B. Motion of molten metals inside the earth’s core

C. Induction effect of the sun

D. Gravitational field of the earth

Ans: B

Explanation: Circulating molten iron in the core creates the geomagnetic field.

2. The magnetic dipole moment of a current loop depends on

A. Area of loop only

B. Current only

C. Both current and area

D. Neither current nor area

Ans: C

Explanation: M = I × A, depends on both.

3. The SI unit of magnetic dipole moment is

A. A·m

B. A/m

C. A·m²

D. Wb/m²

Ans: C

Explanation: Unit comes from M = I × A.

4. The angle of dip at the magnetic equator is

A. 0°

B. 30°

C. 60°

D. 90°

Ans: A

Explanation: At equator, earth’s magnetic field is horizontal.

5. The angle of dip at magnetic poles is

A. 0°

B. 45°

C. 60°

D. 90°

Ans: D

Explanation: Field is vertical at the magnetic poles.

6. The horizontal component of earth’s magnetic field at a place is BH = B cos δ. Here δ is

A. Angle of declination

B. Angle of dip

C. Latitude

D. Colatitude

Ans: B

Explanation: δ represents the magnetic dip angle.

7. Magnetic meridian is

A. Plane containing magnetic field lines and geographic axis

B. Plane containing magnetic field lines and vertical axis

C. Plane containing magnetic field lines and magnetic axis

D. Plane containing magnetic and electric field

Ans: B

Explanation: It is the vertical plane passing through the magnetic field vector at a place.

8. The earth behaves as

A. Diamagnetic

B. Paramagnetic

C. Ferromagnetic

D. Electromagnetic

Ans: B

Explanation: Earth’s materials exhibit weak paramagnetic behavior overall.

9. A magnetic needle free to rotate in a vertical plane aligns with

A. Geographical meridian

B. Magnetic meridian

C. Horizontal plane

D. None

Ans: B

Explanation: The needle aligns along the magnetic meridian of the earth.

10. The magnetic declination is the angle between

A. Magnetic meridian and geographical meridian

B. Magnetic axis and equator

C. Magnetic field and horizontal plane

D. None

Ans: A

Explanation: Declination is the horizontal angle between true north and magnetic north.

11. If the magnetic dip at a place is 60°, then the vertical component of magnetic field is

A. 0.5 B

B. 0.707 B

C. 0.866 B

D. B

Ans: C

Explanation: BV = B sin 60° = 0.866 B.

12. The magnetic moment of a solenoid is directly proportional to

A. Length

B. Area

C. Number of turns

D. Both B and C

Ans: D

Explanation: M = NIA; depends on both area and number of turns.

13. A bar magnet is placed in earth’s magnetic field. It experiences

A. Only torque

B. Only force

C. Both torque and force

D. Neither

Ans: A

Explanation: Torque acts to align the magnet; no net force in a uniform field.

14. If a magnet is cut into two equal halves along its length, magnetic moment of each part is

A. Same

B. Half

C. Double

D. Zero

Ans: B

Explanation: Magnetic moment halves as pole strength becomes half, length same.

15. Magnetic susceptibility χ is

A. Positive for diamagnetic

B. Positive for paramagnetic

C. Negative for diamagnetic

D. Both B and C

Ans: D

Explanation: Diamagnetic χ < 0, Paramagnetic χ > 0 (small positive).

16. Ferromagnetism disappears above

A. Melting point

B. Curie temperature

C. Boiling point

D. Saturation point

Ans: B

Explanation: Above Curie temperature, material becomes paramagnetic.

17. The Curie temperature for iron is

A. 770 K

B. 273 K

C. 500 K

D. 1200 K

Ans: A

Explanation: Iron loses ferromagnetism above 770 K.

18. A diamagnetic substance is one which

A. Weakly repelled by a magnet

B. Weakly attracted

C. Strongly attracted

D. Strongly repelled

Ans: A

Explanation: Diamagnetic materials are weakly repelled by magnetic fields.

19. Magnetic intensity H and magnetic induction B are related as

A. B = μH

B. B = H/μ

C. H = μB

D. None

Ans: A

Explanation: B = μH = μ₀(1 + χ)H.

20. The value of magnetic susceptibility for perfect diamagnetics is

A. 0

B. +1

C. −1

D. Infinity

Ans: C

Explanation: Perfect diamagnetics expel all magnetic field, χ = −1.

21. The unit of magnetic susceptibility is

A. A·m²

B. No unit

C. Wb/m²

D. Tesla

Ans: B

Explanation: It’s dimensionless (ratio of M to H).

22. Permanent magnets are made of

A. Soft iron

B. Steel

C. Copper

D. Aluminum

Ans: B

Explanation: Steel retains magnetization strongly.

23. Temporary magnets are made of

A. Steel

B. Soft iron

C. Nickel

D. Cobalt

Ans: B

Explanation: Soft iron is easily magnetized and demagnetized.

24. The magnetic dipole moment of an electron due to orbital motion is

μ = (eL) / (2m)

Ans: μ = eL / 2m

Explanation: Arises from current loop formed by electron’s motion.

25. The Bohr magneton value is

A. 9.27 × 10⁻²⁴ J/T

B. 1.6 × 10⁻¹⁹ J/T

C. 6.63 × 10⁻³⁴ J/T

D. 10⁻¹⁰ J/T

Ans: A

Explanation: μB = eħ / 2me = 9.27 × 10⁻²⁴ J/T.

26. A paramagnetic substance obeys

A. Curie’s law

B. Coulomb’s law

C. Ohm’s law

D. None

Ans: A

Explanation: χ = C / T (Curie’s Law).

27. The magnetic field at the center of a bar magnet behaves as

A. Dipole field

B. Uniform field

C. Monopole field

D. None

Ans: A

Explanation: A bar magnet is equivalent to a magnetic dipole.

28. The work done in rotating a magnetic dipole in a uniform magnetic field is

W = MB (cos θ₁ − cos θ₂)

Ans: As shown

Explanation: Torque = MB sin θ, integrate to find work done.

29. In tangent galvanometer, if plane of coil is in magnetic meridian, then deflection is

A. Maximum

B. Minimum

C. Zero

D. Infinite

Ans: A

Explanation: Coil field ⟂ Earth’s field, giving maximum deflection.

30. Neutral points in a bar magnet are the points where

A. Resultant field is zero

B. Only horizontal field acts

C. Only vertical field acts

D. None

Ans: A

Explanation: Field due to magnet cancels Earth’s field at neutral points.