Magnetism and Matter Class 12 Important Questions 2026-27 | CBSE Physics
CBSE Class 12 Physics • Chapter 5
Magnetism and Matter — Important Questions
Exam-oriented questions and answer frameworks for CBSE Class 12 Physics 2026–27, aligned to the current Chapter 5 scope.
1-mark concepts2-mark answers3-mark questionsBoard-style practiceHow to Use These Important Questions
First read the Magnetism and Matter Class 12 Physics Notes. Then attempt the questions without opening the answer. After checking, rewrite weak answers in your own words using the scientific terms shown in the answer framework.
Attempt Sections A and B after studying the relevant concept.
Write the 3-mark answers under a short time limit and check whether every required point is present.
Return only to questions you got wrong, partly answered or answered without correct terminology.
Use the Chapter 4 notes when a question connects magnetic dipole ideas with a current-carrying loop.
Section A — 1-Mark Important Questions
These questions target definitions, direct concepts, identification and one-step reasoning. Keep a 1-mark answer precise.
Answer: A magnetic dipole is a system having two equal and opposite magnetic poles separated by a small distance. A bar magnet is a common example.
Answer: For a bar magnet, the magnetic dipole moment is directed from the south pole to the north pole inside the magnet.
Answer: A magnetic field line is an imaginary curve whose tangent at any point gives the direction of the magnetic field at that point.
Answer: No. If they intersected, the tangent at the intersection would give two different directions of the magnetic field at the same point.
Answer: By convention, the direction of the magnetic field at a point is the direction in which the north pole of a small test magnet would move; outside a bar magnet this is from its north pole toward its south pole.
Answer: For a coil of N turns, current I and area A: m = NIA Its SI unit is A m2.
Answer: The torque on it is zero because θ = 0° and τ = mB sin θ.
Answer: The torque is maximum when the dipole moment is perpendicular to the magnetic field, i.e. θ = 90°.
Answer: Diamagnetic, paramagnetic and ferromagnetic materials.
Answer: It is weakly repelled by the applied magnetic field and develops an induced magnetic response opposite to the applied field.
Answer: It is weakly attracted by an applied magnetic field.
Answer: Ferromagnetic materials.
Answer: Diamagnetic: bismuth; paramagnetic: aluminium; ferromagnetic: iron. Other valid textbook examples may also be used.
Answer: Magnetisation is the magnetic dipole moment developed per unit volume of a material.
Answer: A m−1.
Answer: Its strong ferromagnetic behaviour is lost; above the Curie temperature it behaves as a paramagnetic material.
Section B — 2-Mark Important Questions
Answer framework:
- A bar magnet has two opposite magnetic poles separated by a finite distance.
- The pair behaves as a dipole and produces a characteristic magnetic field around it.
Answer framework: A current-carrying solenoid produces a magnetic field pattern similar to that of a bar magnet. The face of the solenoid behaves like a magnetic pole depending on current direction, so the solenoid can be used as a physical model for understanding the magnetic dipole nature of a bar magnet. For the current syllabus, keep this comparison primarily qualitative.
- The tangent to a field line at a point gives the direction of the magnetic field there.
- Magnetic field lines form continuous closed curves; they do not begin or end at an isolated magnetic pole.
Answer: The density of field lines is used as a visual representation of relative field strength. A greater concentration of lines in a region represents a stronger magnetic field there.
Torque is maximum at θ = 90° and zero at θ = 0° or 180°.
Answer: The magnetic forces on the two poles of the dipole are equal and opposite in a uniform field, so the net force is zero. However, their lines of action are separated, forming a couple that produces torque and tends to align the dipole moment with the field.
| Diamagnetic | Paramagnetic |
|---|---|
| Weakly repelled by an applied field. | Weakly attracted by an applied field. |
| Induced magnetic response is opposite to the applied field. | Net magnetic response is along the applied field. |
| Paramagnetic | Ferromagnetic |
|---|---|
| Weak attraction to an external magnetic field. | Strong attraction to an external magnetic field. |
| Magnetic response is comparatively weak. | Can acquire strong magnetisation and may retain it after the external field is removed. |
Answer: Magnetisation is the magnetic dipole moment per unit volume of a material. It represents the net magnetic response of the material on a macroscopic scale when microscopic magnetic moments respond to an external magnetic field.
Answer: Increasing temperature increases thermal agitation, which disturbs the alignment responsible for magnetic ordering. In ferromagnetic materials, sufficiently high temperature can destroy the ordered ferromagnetic state; above the Curie temperature the material becomes paramagnetic.
Section C — 3-Mark Important Questions
Answer framework:
- Along the axis of the magnet, the field is directed along the magnet's axial field pattern and is relatively stronger near the magnet.
- At a point on the perpendicular/equatorial line through the centre, the field direction is opposite to the magnetic dipole moment for the external field convention.
- In both cases, field strength decreases as the observation point is moved farther away; the current syllabus requires a qualitative treatment rather than a formula-heavy derivation.
Answer framework:
- A current-carrying solenoid produces a field resembling that of a bar magnet.
- The two ends of the solenoid behave like opposite magnetic poles.
- This analogy provides a bridge between magnetism produced by electric current and the dipole behaviour of a permanent magnet.
| Angle θ | Torque | Interpretation |
|---|---|---|
| 0° | 0 | Dipole moment is parallel to the field. |
| 90° | mB | Torque is maximum. |
| 180° | 0 | Dipole moment is antiparallel to the field. |
| Type | Response | Example |
|---|---|---|
| Diamagnetic | Weakly repelled | Bismuth |
| Paramagnetic | Weakly attracted | Aluminium |
| Ferromagnetic | Strongly attracted; strong magnetisation possible | Iron |
Exam tip: Do not write only the examples. The classification earns its value from the physical distinction.
Answer framework: Magnetic materials contain microscopic magnetic moments. In an unmagnetised sample, their orientations may give little or no net magnetic moment. An applied magnetic field changes the alignment of these microscopic moments to some extent, producing a net magnetic dipole moment per unit volume called magnetisation.
Answer framework:
- Thermal agitation becomes stronger as temperature rises.
- Magnetic ordering becomes less stable.
- At the Curie temperature, the ferromagnetic state is lost; above it, the material behaves as a paramagnet.
Use m = NIA
Substitute: m = 50 × 0.20 × 4.0 × 10−3 = 4.0 × 10−2 A m2.
Writing point: Always include the SI unit of magnetic dipole moment.
Use τ = mB sin θ
τ = 0.50 × 0.20 × sin 30° = 0.050 N m.
Official 2026–27 SQP-Linked Extension
Answer: A relative permeability much greater than 1 is characteristic of a ferromagnetic material.
- Ferromagnetic materials show strong attraction and can develop strong magnetisation.
- They can retain magnetisation under suitable conditions and are associated with magnetic ordering.
Meaning: The net magnetic flux through any closed surface is zero. It is consistent with the fact that isolated magnetic monopoles are not observed in classical electromagnetism and magnetic field lines form continuous closed curves.
Answer: No. Gauss’s law concerns the net flux through the entire closed surface. Magnetic field can pass into and out of different parts of the surface, while the total signed flux remains zero.
Integrated Board-Style Questions
These combine more than one idea and are useful after the basic questions are secure.
Answer: Both have two opposite magnetic ends; both produce similar dipole-like external field patterns; and the orientation of the solenoid's magnetic polarity depends on the direction of current, just as a magnet has a definite north–south orientation.
Answer: At 90°, the torque is maximum. The torque acts to rotate the dipole so that its magnetic dipole moment moves toward alignment with the magnetic field. When the dipole reaches the parallel orientation, the torque becomes zero.
Answer: The weakly repelled material is diamagnetic; its induced magnetic response opposes the applied field. The strongly attracted material is ferromagnetic; it can develop a very strong magnetic response because of magnetic ordering.
Common Answer-Writing Traps
Final Chapter 5 Revision Checklist
- I can define a magnetic dipole and magnetic dipole moment.
- I can explain the bar magnet as an equivalent solenoid qualitatively.
- I can describe magnetic field lines and their important properties.
- I can distinguish axial and perpendicular/equatorial positions qualitatively.
- I can use τ = mB sin θ and interpret 0°, 90° and 180°.
- I can define magnetisation and state its SI unit.
- I can distinguish diamagnetic, paramagnetic and ferromagnetic materials.
- I can give valid examples for all three classes.
- I can explain why temperature changes magnetic behaviour and what happens above the Curie temperature.
- I can write concise, point-wise answers using correct physics terminology.
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