Magnetism and Matter — Class 12 Physics NCERT Solutions (Free)

Free step-by-step NCERT solutions for Class 12 Physics chapter "Magnetism and Matter" — 6 important questions with detailed answers for CBSE board exam preparation.

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TL;DR: Free step-by-step NCERT solutions for Class 12 Physics chapter "Magnetism and Matter" — 6 important questions with detailed answers for CBSE board exa…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 23, 2026

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Key Questions Covered:

Define magnetic susceptibility. Write its relation with relative permeability.
What is magnetic permeability? Distinguish between μ, μ₀, and μᵣ.
What are diamagnetic materials? Explain diamagnetism from electronic structur…
What are paramagnetic materials? Explain paramagnetism with examples.
What are ferromagnetic materials? Define and explain ferromagnetism.
Define magnetic field intensity (H) and magnetization (M). Write relation bet…

Solutions Summary:

Question	Status
Define magnetic susceptibility. Write its relation with r…	✓ Solved
What is magnetic permeability? Distinguish between μ, μ₀,…	✓ Solved
What are diamagnetic materials? Explain diamagnetism from…	✓ Solved
What are paramagnetic materials? Explain paramagnetism wi…	✓ Solved
What are ferromagnetic materials? Define and explain ferr…	✓ Solved
Define magnetic field intensity (H) and magnetization (M)…	✓ Solved

Showing 6 of 6 questions

Q1: Define magnetic susceptibility. Write its relation with relative permeability.

Magnetic Susceptibility (χ_m - chi): Measure of ease with which material gets magnetized. χ_m = M/H where M = magnetization (magnetic moment per unit volume) H = magnetic field intensity Dimensionless quantity (no units) Relation with Relative Permeability: μᵣ = 1 + χ_m where μᵣ = relative permeability Alternative: B = μ₀(H + M) = μ₀(1 + χ_m)H = μ₀μᵣH Classification of Materials: 1. Diamagnetic: χ_m < 0 (small negative) μᵣ < 1 (slightly less than 1) Examples: Copper, bismuth,...

Q2: What is magnetic permeability? Distinguish between μ, μ₀, and μᵣ.

Magnetic Permeability (μ): Ability of material to support magnetic field. μ = B/H where B = magnetic flux density H = magnetic field intensity SI Unit: Henry per meter (H/m) or T⋅m/A Alternatively: T⋅m/A or Wb/(A⋅m) Three types: 1. Absolute Permeability (μ): μ = B/H Dimension: [H/m] or [T⋅m/A] Value depends on material Used in material science 2. Permeability of Free Space (μ₀): μ₀ = 4π × 10⁻⁷ H/m = 4π × 10⁻⁷ T⋅m/A Constant for vacuum and air Fundamental constant in electromagnetism 3. Re...

Q3: What are diamagnetic materials? Explain diamagnetism from electronic structure viewpoint.

Diamagnetic Materials: Materials that are weakly repelled by magnetic field. Characteristics: - Magnetic susceptibility χ_m < 0 (negative) - Relative permeability μᵣ < 1 (slightly less than 1) - |χ_m| very small (typically 10⁻⁵ to 10⁻⁶) - No permanent magnetic moment - Induced magnetization opposes applied field Examples: Cu, Bi, Sb, Pb, Si, H₂O, N₂, noble gases Electronic Structure Explanation: Origin: Lenz's Law applied to electron motion Step 1: In atoms, electrons orbit nucleus in...

Q4: What are paramagnetic materials? Explain paramagnetism with examples.

Paramagnetic Materials: Materials weakly attracted to magnetic field. Characteristics: - Magnetic susceptibility χ_m > 0 (positive) - Relative permeability μᵣ > 1 (slightly greater than 1) - χ_m small (typically 10⁻³ to 10⁻⁵) - Unpaired electrons in atoms - Permanent atomic magnetic moments - Moments randomly oriented → net moment is zero - Applied field aligns moments → net magnetization - Loses magnetism when field removed Examples: Al, Mn, Fe³⁺, Cu²⁺, O₂, paramagnetic salts Physical ...

Q5: What are ferromagnetic materials? Define and explain ferromagnetism.

Ferromagnetic Materials: Materials strongly attracted to magnetic field and retain magnetization. Characteristics: - Very large positive susceptibility χ_m >> 1 (up to 10⁵) - μᵣ >> 1 (up to 10⁶) - Permanent strong magnetization - Retain magnetism after field removal (remnant magnetism) - Show hysteresis loop - Magnetization saturates at high fields - Lose ferromagnetism above Curie temperature T_c Examples: Fe, Co, Ni, Fe₃O₄, permanent magnets Explanation: Exchange Interaction: Q...

Q6: Define magnetic field intensity (H) and magnetization (M). Write relation between B, H, and M.

Magnetic Field Intensity (H): H = B/μ₀ - M Alternatively: H = (B - μ₀M)/μ₀ SI Unit: A/m (Ampere per meter) Dimension: [A/m] or [A·m⁻¹] Physical meaning: - Due to free currents only (excluding magnetization currents) - Independent of material properties - Measure of applied magnetic field Magnetization (M): M = Σm/V (total magnetic dipole moment per unit volume) SI Unit: A/m (same as H) Dimension: [A/m] Physical meaning: - Magnetic dipole moment density - Measure of material's magnetic resp...

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