Chapter-5 Magnetism and Matter — Online MCQ Test
PHYSICS · Grade 12 · CBSE(NCERT)
Practice Chapter-5 Magnetism and Matter with a free chapter-wise online MCQ test.
This chapter covers: bar magnet - magnetic field lines - Earth's magnetism - paramagnetic - diamagnetic - ferromagnetic materials.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-5 Magnetism and Matter — Important Questions & Answers
What is the SI unit of magnetic dipole moment?
- A. A·m²
- B. T·m
- C. Wb/m
- D. H/m
Answer: A. A·m²
The magnetic dipole moment is measured in Ampere-meter squared (A·m²), which represents the product of current and area.
The magnetic dipole moment is measured in Ampere-meter squared (A·m²), which represents the product of current and area.
Which of the following materials is diamagnetic?
- A. Iron
- B. Cobalt
- C. Copper
- D. Nickel
Answer: C. Copper
Copper is diamagnetic as it has no unpaired electrons and opposes external magnetic fields; iron, cobalt, and nickel are ferromagnetic.
Copper is diamagnetic as it has no unpaired electrons and opposes external magnetic fields; iron, cobalt, and nickel are ferromagnetic.
A paramagnetic material has magnetic susceptibility (χ):
- A. χ > 1 (positive and large)
- B. χ ≈ 10⁻⁵ to 10⁻³ (small and positive)
- C. χ ≈ -10⁻⁶ to -10⁻⁵ (small and negative)
- D. χ = 0
Answer: B. χ ≈ 10⁻⁵ to 10⁻³ (small and positive)
Paramagnetic materials have small positive magnetic susceptibility (χ ≈ 10⁻⁵ to 10⁻³), indicating weak attraction to magnetic fields.
Paramagnetic materials have small positive magnetic susceptibility (χ ≈ 10⁻⁵ to 10⁻³), indicating weak attraction to magnetic fields.
Compare the magnetic susceptibility values: If χ₁ is for aluminum (paramagnetic), χ₂ for bismuth (diamagnetic), and χ₃ for iron (ferromagnetic), then the correct order is:
- A. χ₂ > χ₁ > χ₃
- B. χ₃ > χ₁ > χ₂
- C. χ₁ > χ₃ > χ₂
- D. χ₂ > χ₃ > χ₁
Answer: B. χ₃ > χ₁ > χ₂
Iron (ferromagnetic, χ₃ >> 1) > Aluminum (paramagnetic, χ₁ ≈ 10⁻⁵) > Bismuth (diamagnetic, χ₂ ≈ -10⁻⁵). Ferromagnetic > Paramagnetic > Diamagnetic.
Iron (ferromagnetic, χ₃ >> 1) > Aluminum (paramagnetic, χ₁ ≈ 10⁻⁵) > Bismuth (diamagnetic, χ₂ ≈ -10⁻⁵). Ferromagnetic > Paramagnetic > Diamagnetic.
The relationship between magnetic field B, permeability μ, and magnetization M in a material is B = μ₀(H + M). When a ferromagnetic material is magnetized near saturation, M becomes:
- A. Very large compared to H, making B ≈ μ₀M
- B. Zero, making B = μ₀H
- C. Negative
- D. Equal to H
Answer: A. Very large compared to H, making B ≈ μ₀M
Near saturation of a ferromagnetic material, magnetization M becomes very large (as all domains align), so M >> H and B ≈ μ₀M dominates the expression.
Near saturation of a ferromagnetic material, magnetization M becomes very large (as all domains align), so M >> H and B ≈ μ₀M dominates the expression.