Class 9 Physics Chapter 5 Magnetism and Matter MCQ with Answers – 30 Questions (Easy to Hard)

The 2024–25 CBSE Physics curriculum emphasizes competency-based assessment over rote memorization. MCQs are the preferred vehicle for testing this because they measure conceptual clarity, application skills, and decision-making speed—all critical in competitive exams like JEE Main and NEET. In the new CBSE pattern, one-mark MCQs typically appear in Part A of Term 1 and Term 2 assessments, while assertion–reason MCQs (2 marks) test deeper understanding. For Chapter 5 specifically, examiners focus on: (i) magnetic field lines and Earth's magnetic field properties, (ii) magnetic vs. non-magnetic materials, and (iii) the origin of Earth's magnetism. Studies show students who practice 30+ MCQs before the exam score 15–20% higher than those who skip this step. MCQs also train you to eliminate wrong answers quickly—a skill that saves precious time during exams. Unlike descriptive questions, MCQs force you to commit to one answer, reducing guesswork and building confidence. By working through easy, medium, and hard tiers, you'll develop pattern recognition skills that apply to unseen questions on test day.

**Q1.** The magnetic field lines around a bar magnet: (A) Form closed loops inside the magnet (B) Never intersect each other (C) Are densest at the poles (D) All of the above **Answer:** (D) All of the above **Reason:** Magnetic field lines always form closed loops, never intersect (unique field direction at each point), and compress near poles where field strength is maximum. **Q2.** What is the angle of dip at the magnetic equator? (A) 0° (B) 45° (C) 90° (D) 180° **Answer:** (A) 0° **Reason:** At the magnetic equator, Earth's magnetic field is horizontal, so the angle between field and horizontal plane is 0°. **Q3.** A magnetic material that retains magnetism after the external field is removed is called: (A) Diamagnetic (B) Paramagnetic (C) Ferromagnetic (D) Non-magnetic **Answer:** (C) Ferromagnetic **Reason:** Ferromagnetic materials (Fe, Co, Ni) have aligned atomic magnets; they retain magnetism permanently even when the external field is switched off. **Q4.** Which of the following is NOT a property of magnetic field lines? (A) They form closed loops (B) They repel each other (C) They pass through all materials (D) They are denser near poles **Answer:** (B) They repel each other **Reason:** Field lines represent field direction and strength; they do not physically repel. Lines only intersect in regions with undefined field direction (not present in normal dipole fields). **Q5.** The SI unit of magnetic field strength is: (A) Ampere (A) (B) Tesla (T) (C) Weber (Wb) (D) Gauss (G) **Answer:** (B) Tesla (T) **Reason:** Tesla (T) = Weber/m² measures magnetic flux density; 1 T = 10⁴ Gauss. **Q6.** Earth's magnetic poles are approximately located at: (A) Geographic poles (B) 11° away from geographic poles (C) The equator (D) Random locations **Answer:** (B) 11° away from geographic poles **Reason:** The magnetic poles do not coincide with geographic (rotational) poles; the angle between them is called magnetic declination (≈ 11°). **Q7.** A material whose atoms have no permanent magnetic moment is: (A) Ferromagnetic (B) Paramagnetic (C) Diamagnetic (D) Magnetic **Answer:** (C) Diamagnetic **Reason:** Diamagnetic materials have paired electrons with no net permanent dipole; they are weakly repelled by external fields. **Q8.** The angle between magnetic field and horizontal at a location is called: (A) Magnetic declination (B) Magnetic inclination (dip) (C) Magnetic variation (D) Magnetic deviation **Answer:** (B) Magnetic inclination (dip) **Reason:** Dip angle = angle between Earth's magnetic field vector and horizontal plane; measured in the vertical plane. **Q9.** Which statement about Earth's magnetism is true? (A) It is caused by moving charges in Earth's liquid outer core (B) It remains constant over centuries (C) Magnetic poles coincide with geographic poles (D) Earth's magnetic field has only one pole **Answer:** (A) It is caused by moving charges in Earth's liquid outer core **Reason:** Convection currents of molten iron in the outer core generate Earth's magnetic field (dynamo theory); it is dynamic and varies over time. **Q10.** A compass needle aligns with: (A) Geographic north (B) Magnetic north (C) True magnetic field at that location (D) The equator **Answer:** (C) True magnetic field at that location **Reason:** Compass needles align parallel to Earth's magnetic field lines at that geographic location, which points roughly (but not exactly) toward magnetic north.

**Q11.** A vertical magnetic field of magnitude B is applied. A horizontal current-carrying wire is placed perpendicular to this field. The force on the wire will: (A) Always be horizontal (B) Always be vertical (C) Be perpendicular to both current and field (D) Be parallel to the current **Answer:** (C) Be perpendicular to both current and field **Reason:** The magnetic force F = I(L × B) is always perpendicular to both current direction and field (right-hand rule); it will be horizontal in this case. **Q12.** Two bar magnets are placed with their south poles facing each other. The force between them will be: (A) Attractive (B) Repulsive (C) Zero (D) Depends on the strength of magnets **Answer:** (B) Repulsive **Reason:** Like poles (S–S or N–N) always repel; unlike poles attract. Pole strength and distance affect magnitude but not the direction. **Q13.** The angle of inclination at a place where the horizontal and vertical components of Earth's field are equal (BH = BV): (A) 30° (B) 45° (C) 60° (D) 90° **Answer:** (B) 45° **Reason:** tan(δ) = BV/BH; when BV = BH, tan(δ) = 1, so δ = 45°. **Q14.** A soft iron rod is placed inside a solenoid carrying AC current. After the current stops, the rod will: (A) Remain permanently magnetized (B) Lose its magnetism immediately (C) Retain some residual magnetism (D) Explode due to induced currents **Answer:** (B) Lose its magnetism immediately **Reason:** Soft iron has very low remanence (residual magnetism) and high coercivity threshold; it demagnetizes quickly when the external field is removed. **Q15.** The magnetic field at the center of a circular loop of radius r carrying current I is: (A) μ₀I/(2r) (B) μ₀I/(πr) (C) μ₀I/(2πr) (D) Cannot be determined **Answer:** (A) μ₀I/(2r) **Reason:** Using Biot-Savart law, B = μ₀I/(2r) at the center of a single circular loop (μ₀ = 4π × 10⁻⁷ T·m/A). **Q16.** When a bar magnet is broken into two pieces along its length: (A) Each piece loses all magnetism (B) Each piece becomes a new dipole with N and S poles (C) One piece becomes N-pole, the other S-pole (D) The pieces repel each other violently **Answer:** (B) Each piece becomes a new dipole with N and S poles **Reason:** Magnetic monopoles do not exist; breaking a magnet produces two smaller dipoles, each with their own N and S poles. **Q17.** A paramagnetic material is placed in a non-uniform magnetic field. It will: (A) Move away from the stronger field region (B) Move toward the stronger field region (C) Remain stationary (D) Oscillate back and forth **Answer:** (B) Move toward the stronger field region **Reason:** Paramagnetic materials are weakly attracted to strong fields because their atoms align with the field, creating a net dipole moment in that direction. **Q18.** The magnetic susceptibility χ of a paramagnetic material is typically: (A) Large and negative (χ < −1) (B) Small and negative (−1 < χ < 0) (C) Small and positive (0 < χ < 1) (D) Large and positive (χ > 1) **Answer:** (C) Small and positive (0 < χ < 1) **Reason:** Paramagnetic materials are weakly magnetized by external fields; χ is positive but very small (10⁻³ to 10⁻⁵), much smaller than ferromagnetic materials. **Q19.** If the magnetic field strength at a point due to Earth's magnetism is B, and a bar magnet is placed horizontally at that location, the resultant field will: (A) Always increase (B) Always decrease (C) Depend on the magnet's orientation (D) Become zero **Answer:** (C) Depend on the magnet's orientation **Reason:** Resultant field = vector sum of Earth's field + magnet's field; magnitude depends on angle between them. If parallel, fields add; if antiparallel, they subtract. **Q20.** The magnetic field inside a uniformly magnetized rod is: (A) Zero (B) Uniform and equal to Earth's field (C) Uniform but less than the field at the poles (D) Non-uniform and strongest at the center **Answer:** (C) Uniform but less than the field at the poles **Reason:** Inside a uniformly magnetized material, the field is uniform but weaker than at the poles because internal dipoles partially cancel the external field effect.

**Q21. Assertion (A):** Earth's magnetic poles reverse periodically over geologic timescales. **Reason (R):** The liquid outer core's convection pattern changes due to variations in radioactive decay rates. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (C) A is true, but R is false **Reason:** Magnetic reversals do occur (proven by paleomagnetic records), but the precise cause is still debated; radioactive decay changes are too slow. Chaotic fluctuations in dynamo action are more likely culprits. **Q22. Assertion (A):** A diamagnetic material placed in a non-uniform magnetic field will experience a force toward the weaker field region. **Reason (R):** Diamagnetic materials have χ < 0 and are repelled by external magnetic fields. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (A) Both A and R are true, and R is the correct explanation **Reason:** Diamagnetic materials are weakly repelled (χ ≈ −10⁻⁵ to −10⁻⁶); in non-uniform fields, they migrate toward regions of lower field strength. **Q23. Assertion (A):** The vertical component of Earth's magnetic field is zero at the magnetic equator. **Reason (R):** The dip angle at the equator is 90°. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (C) A is true, but R is false **Reason:** A is correct: BV = 0 at the magnetic equator. R is false: dip angle δ = 0° at the equator, not 90°. Dip = 90° at the magnetic poles. **Q24. Assertion (A):** The magnetism of a ferromagnetic material can be completely removed by heating it above the Curie temperature. **Reason (R):** Above Curie temperature, thermal energy overcomes the atomic magnetic moment alignment, randomizing dipole directions. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (A) Both A and R are true, and R is the correct explanation **Reason:** Both statements are correct. Curie temperature (e.g., 770 K for iron) is the threshold above which spontaneous ferromagnetism disappears; the material becomes paramagnetic. **Q25. Assertion (A):** When two identical bar magnets are placed end-to-end with opposite poles touching (N–S), the resultant magnetic field at the midpoint between them is zero. **Reason (R):** The magnetic field contributions from each magnet cancel due to symmetric placement and opposite pole configuration. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is false, but R is true (D) Both A and R are false **Answer:** (D) Both A and R are false **Reason:** The field at the midpoint is NOT zero. Although poles are opposite, both magnets' field lines point in the same direction along the axis, so fields add, not cancel. **Q26. Assertion (A):** A compass needle placed near a bar magnet will align with the bar magnet's field, not Earth's field. **Reason (R):** The bar magnet's field is always stronger than Earth's field (≈ 25–65 μT). (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (B) Both A and R are true, but R is not the correct explanation **Reason:** A is true: nearby bar magnets dominate. R is true numerically but incomplete: field strength matters, but so does the magnet's proximity and dipole moment. **Q27. Assertion (A):** Soft iron is preferred over permanent magnets in electromagnets because it demagnetizes quickly when current stops. **Reason (R):** Soft iron has low remanence and low coercivity compared to hardened steel. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (A) Both A and R are true, and R is the correct explanation **Reason:** Soft iron is ideal for electromagnets because it exhibits minimal hysteresis; low remanence means minimal residual magnetism after current stops, and low coercivity means easy demagnetization. **Q28. Assertion (A):** The relationship B = μ₀(H + M) shows that the total magnetic field in a material depends on both the applied field H and the material's magnetization M. **Reason (R):** In paramagnetic materials, M is always proportional to H and in the same direction. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (B) Both A and R are true, but R is not the correct explanation **Reason:** Both are true. A explains the general relationship correctly. R is true for paramagnetic materials (M ∝ H, χ > 0), but the reason doesn't explain why B = μ₀(H + M); it only describes a special case. **Q29. Assertion (A):** A solenoid carrying DC current will produce a magnetic field with the same pattern as a bar magnet. **Reason (R):** The solenoid's field results from vector addition of circular current loops, which aligns to produce a dipole-like field. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (A) Both A and R are true, and R is the correct explanation **Reason:** Both are correct. A solenoid's field pattern mirrors a bar magnet (N and S poles, field lines). R explains the physics: stacked circular loop fields combine to produce the dipole pattern. **Q30. Assertion (A):** At a location where magnetic declination is 15° west, a compass needle points 15° west of true (geographic) north. **Reason (R):** Magnetic declination is the angle between true north and magnetic north at a given location. (A) Both A and R are true, and R is the correct explanation (B) Both A and R are true, but R is not the correct explanation (C) A is true, but R is false (D) Both A and R are false **Answer:** (A) Both A and R are true, and R is the correct explanation **Reason:** Both are correct. Magnetic declination is precisely defined as the angle between geographic north and magnetic north. A compass points toward magnetic north, so it deviates from true north by the declination angle.

CBSE examiners craft distractor options that exploit common misconceptions. Recognizing these traps saves you from careless mistakes: **Trap 1: Confusing Dip Angle with Declination** Students often mix up dip (inclination, δ) and declination (D). Dip is the angle between Earth's field and the horizontal plane (measured in the vertical plane). Declination is the angle between true north and magnetic north (measured in the horizontal plane). Example: "At location X, the magnetic field makes 40° with horizontal; what is the declination?" Answer: Cannot determine from dip alone; declination requires additional info. **Trap 2: Assuming Magnetic Poles Behave Like Electric Charges** While both follow inverse-square laws, magnetic monopoles do NOT exist. Breaking a magnet creates two dipoles, not separate N and S poles. A distractor might claim "isolating a magnetic monopole is theoretically possible"—false in classical physics. **Trap 3: Misinterpreting "Magnetic Field Inside a Material"** Inside a uniformly magnetized material, the field is weaker than outside (near poles) because interior dipoles partially cancel the externally applied field. A trap option: "The field inside is stronger." This confuses students who think all material increases the field. **Trap 4: Confusing Susceptibility Signs** χ < 0 = diamagnetic (repelled). χ > 0 = paramagnetic or ferromagnetic (attracted). A trap: "Diamagnetic materials have positive susceptibility." Wrong. Another trap: "All paramagnetic materials have the same χ value." Wrong—χ varies with material and temperature. **Trap 5: Equating Magnetic Strength with Field Direction** A strong magnet's field is stronger, but field *direction* is still along the axis (N to S outside, S to N inside). Trap: "A strong bar magnet creates field lines in all directions." False—field pattern is the same; only magnitude changes. **Trap 6: Overestimating Earth's Magnetic Field Strength** Earth's field (≈ 25–65 μT) is weak. Students assume nearby lab magnets are weaker. Trap: "Earth's magnetic field is the strongest field we measure in physics." False—lab electromagnets and permanent magnets far exceed it. This affects how we analyze compass alignment near magnets. **Trap 7: Misunderstanding Hysteresis in Ferromagnetic Materials** Hysteresis is the lag between applied field H and magnetization M; it indicates energy loss. A trap: "Hysteresis means the material opposes magnetization." Partially true but misleading—hysteresis reflects domain wall movement friction, not pure opposition. **Trap 8: Confusing Curie Temperature with Melting Point** A magnet heated to Curie temperature (e.g., 770 K for Fe) loses ferromagnetism but remains solid. Trap: "Iron loses magnetism only when it melts." False—melting point ≈ 1811 K, far above Curie temp. Also: "Cooling below Curie temperature always restores original magnetism." False—unless the external field is reapplied. **Trap 9: Oversimplifying Soft vs. Hard Iron Distinction** Soft iron has low coercivity (easy to magnetize/demagnetize, low remanence). Hard steel has high coercivity (hard to magnetize/demagnetize, high remanence). A trap: "Soft iron is physically softer than hard steel." Wrong—'soft' and 'hard' refer to magnetic properties, not mechanical hardness. **Trap 10: Ignoring Vector Nature of Magnetic Field** B is a vector. When two fields overlap, you must add them vectorially, not algebraically. Trap: "Two magnets placed 5 cm apart: their fields add to 2B." Only true if fields are parallel and point the same direction. If antiparallel, resultant could be B, 0, or 2B depending on geometry. This often appears in assertion–reason questions designed to catch careless solvers.

Scoring high on MCQs isn't just about knowledge—it's about speed and strategic decision-making. Here's a proven 3-step approach used by top CBSE scorers: **Step 1: The 45-Second Rule (Easy MCQs)** For easy MCQs (questions Q1–Q10 level), allocate 30–45 seconds per question. If an easy MCQ takes you more than 45 seconds, you're overthinking. Strategy: Read the question once, eliminate obviously wrong options (usually 1–2), then commit to your best answer. Example: "The SI unit of magnetic field is..." You should answer in under 20 seconds because it's direct recall. Mark a checkmark and move on; don't second-guess. **Step 2: The 75-Second Strategy (Medium MCQs)** Medium MCQs (Q11–Q20 level) require concept application and may involve a quick calculation (e.g., dip angle from tan θ = BV/BH). Allocate 60–75 seconds. Strategy: (i) Identify what the question tests (concept or formula). (ii) Sketch a quick diagram if needed (e.g., field lines, angle setup). (iii) Calculate or reason through options. Example: "If BH = BV, find dip angle." Write tan θ = 1, so θ = 45°. Answer in ~60 seconds. **Step 3: The 2-Minute Rule (Hard/Assertion–Reason MCQs)** Assertion–reason questions (Q21–Q30 level) are multi-step. Each statement must be evaluated independently, then checked against four possible relationships. Allocate 90–120 seconds per question. Strategy: (i) Evaluate Assertion: True or False? (ii) Evaluate Reason: True or False? (iii) Check if Reason explains Assertion. Use this decision tree: - Both True + Reason explains Assertion → Option A - Both True but Reason doesn't explain → Option B - A True, R False → Option C - Both False → Option D Example: Q21 (Earth's poles reverse). Take 30 sec to decide A is true (yes, reversals happen). Take 40 sec to evaluate R (radioactive decay as cause—debated and incomplete). Conclude: A true, R weak or misleading. Answer: C or B depending on phrasing. Total: ~100 seconds. **Bonus: The Flagging Technique** If a question isn't immediately clear, flag it (mentally or on paper) and come back. In a 1-hour exam with 30 MCQs: - Spend 15 minutes on easy (30 questions × 30 sec = 15 min). - Spend 20 minutes on medium (20 questions × 60 sec = 20 min). - Spend 20 minutes on hard (10 questions × 120 sec = 20 min). - Reserve 5 minutes for review and flagged questions. This leaves 5 minutes buffer for difficult questions you can skip and revisit if time permits. Practicing with cbsetutor.ai's timed MCQ mode helps internalize this rhythm before the exam. **Final Tip: Confidence Matters** If you're confident in your answer, don't change it. Statistics show first instincts are correct 70–80% of the time. Only reconsider if you realize you misread the question or made a calculation error. Start a 3-day free trial at cbsetutor.ai to practice timed MCQ sets and refine your strategy in a real exam environment.

**Magnetic Field & Earth's Magnetism:** - Dip Angle (δ): tan(δ) = BV/BH, where BV = vertical component, BH = horizontal component. - At magnetic equator: δ = 0°, BV = 0, BH = max (≈ 30 μT). - At magnetic poles: δ = 90°, BH = 0, BV = max (≈ 60 μT). - Magnetic Declination (D): Angle between geographic north and magnetic north; varies by location and time (e.g., 15° W means compass points 15° west of true north). **Magnetic Field from Current:** - Circular Loop (at center): B = μ₀I/(2r), μ₀ = 4π × 10⁻⁷ T·m/A. - Solenoid (inside, uniform field): B = μ₀nI, where n = turns per unit length. - Long Straight Wire: B = μ₀I/(2πr) at distance r. **Material Magnetism:** - Magnetization: M = χH, where χ = magnetic susceptibility. - Total Field: B = μ₀(H + M) = μ₀(1 + χ)H = μ₀μᵣH, where μᵣ = relative permeability. - Diamagnetic: χ ≈ −10⁻⁵ to −10⁻⁶ (weakly repelled by field). - Paramagnetic: χ ≈ +10⁻³ to +10⁻⁵ (weakly attracted to field). - Ferromagnetic: χ >> 1 (strongly attracted; permanent magnetism possible above some threshold; loses ferromagnetism above Curie temperature). **Magnetic Dipole:** - Magnetic dipole moment: p = IA, where I = current, A = loop area. - Torque on dipole in field: τ = p × B = pB sin θ (θ = angle between p and B). - Potential energy: U = −p · B = −pB cos θ. **Key Properties of Magnetic Field Lines:** 1. Form closed loops (no monopoles). 2. Never intersect (unique field direction at each point). 3. Denser near poles (stronger field). 4. Do not physically repel or attract; they represent field direction and relative strength. **Curie Temperature (Tc):** - Iron (Fe): Tc ≈ 770 K; above this, ferromagnetic order breaks down and material becomes paramagnetic. - Nickel (Ni): Tc ≈ 631 K. - Cobalt (Co): Tc ≈ 1115 K. Use this reference sheet during study and before practice exams to anchor key relationships.