Class 9 Science Chapter 4 Exploring Magnets: 30 MCQ Questions with Answers

The updated CBSE assessment framework for Class 9 emphasizes MCQs because they test both knowledge recall and conceptual understanding in a time-efficient manner. MCQs force you to reason through each option rather than rely on partial answers. In Chapter 4 (Exploring Magnets), MCQs often target common misconceptions—for example, confusing magnetic attraction with gravity, or misidentifying the direction of magnetic field lines. Research shows that students who practise 25–30 quality MCQs before the exam improve their accuracy by 15–20%. The new pattern allocates 25–30% of marks to MCQ-based questions, especially in periodic assessments and pre-board tests. Additionally, MCQs develop faster decision-making skills: you learn to eliminate wrong options quickly and recognize keywords like 'always,' 'never,' or 'sometimes.' This quiz is designed to mirror actual exam patterns, including tricky distractors and assertion-reason combinations that test deeper understanding. By solving these questions, you build confidence and reduce exam anxiety.

**Question 1:** Which of the following is a magnetic material? A) Copper B) Iron C) Aluminium D) Plastic **Answer: B) Iron** **Reason:** Iron is a ferromagnetic material that is attracted strongly to magnets; copper, aluminium, and plastic are non-magnetic. **Question 2:** The Earth's magnetic poles are approximately aligned with the geographic poles. True or False? A) True B) False (magnetic poles are ≈11° offset) C) They change daily D) They are perpendicular **Answer: B) False (magnetic poles are ≈11° offset)** **Reason:** Earth's magnetic poles do not coincide exactly with geographic poles; the magnetic declination is about 11° in most regions. **Question 3:** Which pole of a magnet repels the north pole of a compass needle? A) South pole B) North pole C) Both poles equally D) Neither pole **Answer: B) North pole** **Reason:** Like poles repel each other; the north pole of a magnet repels the north pole of a compass. **Question 4:** A compass needle aligns itself along which direction? A) East-West B) North-South C) Random direction D) Vertical **Answer: B) North-South** **Reason:** A compass needle is a small magnet that aligns along Earth's magnetic field lines, pointing approximately north-south. **Question 5:** Which of the following materials is non-magnetic? A) Nickel B) Cobalt C) Wood D) Steel **Answer: C) Wood** **Reason:** Wood is a non-magnetic material; nickel, cobalt, and steel are all ferromagnetic and attracted to magnets. **Question 6:** If you break a bar magnet into two pieces, what will happen? A) Each piece loses magnetism B) One piece becomes magnetic, the other doesn't C) Each piece becomes a separate magnet D) They remain attracted to each other forever **Answer: C) Each piece becomes a separate magnet** **Reason:** Breaking a magnet creates two new magnets, each with its own north and south poles (magnetic dipole nature). **Question 7:** The magnetic field lines emerge from which pole of a magnet? A) South pole B) North pole C) Both poles equally D) The center **Answer: B) North pole** **Reason:** By convention, magnetic field lines exit the north pole and enter the south pole. **Question 8:** What is the SI unit of magnetic field strength? A) Ampere B) Tesla C) Gauss D) Henry **Answer: B) Tesla** **Reason:** Tesla (T) is the SI unit of magnetic flux density; 1 Tesla = 10,000 Gauss. **Question 9:** A magnetic material becomes demagnetized when: A) Cooled to very low temperatures B) Heated above its Curie temperature C) Exposed to sunlight D) Immersed in water **Answer: B) Heated above its Curie temperature** **Reason:** Heating above the Curie temperature disrupts atomic alignment, causing loss of permanent magnetism. **Question 10:** Which of the following is used to make permanent magnets? A) Copper wire B) Soft iron C) Hard steel D) Aluminum foil **Answer: C) Hard steel** **Reason:** Hard steel (high carbon content) retains magnetism well; soft iron is easily magnetized but quickly loses magnetism.

**Question 11:** A compass is placed in Earth's magnetic field. Its needle points towards the magnetic North Pole. Which of the following explains this observation? A) Compass contains a south-seeking magnet B) Compass contains a north-seeking magnet that aligns with Earth's south magnetic pole C) Compass needle is always randomly oriented D) Earth's gravitational field aligns the needle **Answer: B) Compass contains a north-seeking magnet that aligns with Earth's south magnetic pole** **Reason:** The north pole of a compass needle is attracted to Earth's magnetic south pole (near geographic north); this is why it points north. **Question 12:** If a bar magnet is suspended horizontally in Earth's magnetic field, it will: A) Point vertically upward B) Align north-south with north pole pointing toward geographic north C) Spin rapidly D) Remain in random orientation **Answer: B) Align north-south with north pole pointing toward geographic north** **Reason:** Earth's magnetic field exerts a torque on the magnet, aligning it with field lines (roughly north-south). **Question 13:** The strength of a magnet is maximum at: A) The center B) The poles C) Both equally D) Nowhere (uniform throughout) **Answer: B) The poles** **Reason:** Magnetic field strength increases toward the poles; the magnetic field is strongest and most concentrated at the magnetic poles. **Question 14:** When iron filings are sprinkled around a bar magnet, they arrange themselves in: A) Concentric circles B) Straight lines from pole to pole C) Curved paths from north pole to south pole D) Random patterns **Answer: C) Curved paths from north pole to south pole** **Reason:** Iron filings align along magnetic field lines, which curve from north to south pole, visualizing the field pattern. **Question 15:** A magnet loses its magnetism when rubbed with a file made of non-magnetic material. This is because: A) The file removes the magnetic substance B) Random heating and vibration disorder the atomic domains C) The file is non-magnetic D) Friction creates friction heat **Answer: B) Random heating and vibration disorder the atomic domains** **Reason:** Vigorous rubbing causes atomic magnetic domains to randomize their orientation, reducing net magnetism. **Question 16:** Which method can be used to make a permanent magnet from a steel bar? A) Heating the steel bar above its Curie temperature B) Stroking the steel bar repeatedly with a magnet in one direction C) Freezing the steel bar D) Immersing in salt water **Answer: B) Stroking the steel bar repeatedly with a magnet in one direction** **Reason:** Stroking aligns magnetic domains in a consistent direction; repeated unidirectional rubbing converts the material into a permanent magnet. **Question 17:** Earth's magnetic field is believed to be caused by: A) Rotation of Earth B) Movement of molten iron in the outer core C) Solar wind D) Gravitational attraction of the Moon **Answer: B) Movement of molten iron in the outer core** **Reason:** Convection currents of liquid iron in Earth's outer core create a natural electromagnetic field. **Question 18:** The angle between Earth's magnetic meridian and geographic meridian at a location is called: A) Angle of inclination B) Magnetic declination C) Magnetic inclination D) Magnetic deviation **Answer: B) Magnetic declination** **Reason:** Magnetic declination is the angle between true north (geographic) and magnetic north at any given location. **Question 19:** Soft iron is used for making electromagnets because it: A) Remains magnetized permanently B) Can be magnetized and demagnetized easily C) Has high electrical conductivity D) Is cheaper than steel **Answer: B) Can be magnetized and demagnetized easily** **Reason:** Soft iron has low retentivity and loses magnetism quickly when current stops—ideal for electromagnets that need frequent on-off switching. **Question 20:** If the south pole of magnet A is brought close to the north pole of magnet B, the magnets will: A) Repel each other B) Attract each other C) Neither attract nor repel D) Rotate 90° **Answer: B) Attract each other** **Reason:** Unlike poles attract; opposite magnetic poles (south-north) experience attractive force.

**Question 21:** Assertion: A magnetic field cannot be shielded by placing a non-magnetic material between a magnet and a magnetic object. Reason: Magnetic field lines pass through non-magnetic materials. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: A) Both A and R true, R explains A** **Reason:** Non-magnetic materials like wood or plastic do not block magnetic field lines; they pass through unimpeded, so magnetic attraction persists. **Question 22:** Assertion: Iron is more suitable than copper for making permanent magnets. Reason: Iron has higher electrical conductivity than copper. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: C) A true, R false** **Reason:** Iron is better for permanent magnets due to ferromagnetism (not conductivity); copper's higher conductivity is irrelevant to permanent magnetism. **Question 23:** Assertion: When a bar magnet is heated above its Curie temperature, it loses all magnetism permanently. Reason: Heat destroys the magnetic substance itself. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: C) A true, R false** **Reason:** Above Curie temperature, atomic domains randomize, but the substance itself is unchanged; magnetism can return upon cooling below Curie point if domains realign. **Question 24:** Assertion: A freely suspended compass needle points toward Earth's geographic north pole. Reason: Magnetic north and geographic north coincide at all latitudes. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) A false, R true **Answer: C) A true, R false** **Reason:** Compass points toward magnetic north (near geographic north), but they don't coincide; magnetic declination varies with location (≈11° in many regions). **Question 25:** Assertion: The magnetic field strength at the equator of a bar magnet is zero. Reason: The equator is equidistant from both poles. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: A) Both A and R true, R explains A** **Reason:** On the equatorial line, field vectors from N and S poles cancel out; the weak field there represents this balance. **Question 26:** Assertion: Electromagnets can be switched on and off, but permanent magnets cannot. Reason: Permanent magnets contain domains locked in fixed alignment by atomic forces. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: A) Both A and R true, R explains A** **Reason:** Permanent magnet domains are stable; only external forces (heating, strong shocks, or demagnetizing fields) can randomize them. **Question 27:** Assertion: A magnet attracts an unmagnetized iron object because induced magnetism creates opposite poles in the iron. Reason: Magnetic field lines from the magnet polarize electrons in the iron. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: B) Both A and R true, R does not explain A** **Reason:** Induction is correct, but the mechanism involves domain alignment (not just electron polarization); both statements are true, but R is incomplete. **Question 28:** Assertion: When two identical bar magnets are placed with north poles facing each other, the repulsion force increases as they are brought closer. Reason: Magnetic force is inversely proportional to the square of the distance (F ∝ 1/r²). A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: A) Both A and R true, R explains A** **Reason:** Like poles repel with force F ∝ 1/r², so force increases rapidly as distance decreases. **Question 29:** Assertion: A magnet suspended in space will eventually align itself with Earth's magnetic field. Reason: Earth's magnetic field exerts a torque on the magnet's dipole moment. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: A) Both A and R true, R explains A** **Reason:** The magnetic dipole (pole moment) experiences a torque τ = m × B in an external field, causing alignment. **Question 30:** Assertion: A compass placed at the geographic North Pole will not show a clear north direction. Reason: At the geographic North Pole, Earth's magnetic field lines are nearly vertical. A) Both A and R true, R explains A B) Both A and R true, R does not explain A C) A true, R false D) Both false **Answer: A) Both A and R true, R explains A** **Reason:** Near the magnetic poles, field lines are steep/vertical; a horizontal compass needle receives minimal orienting torque, so it spins erratically.

MCQ trap options in Chapter 4 exploit common misconceptions. Recognize and avoid these: **Trap 1: Confusing 'Magnetic North' with 'Geographic North.'** Many students believe the compass points toward the geographic North Pole. In reality, it points toward Earth's magnetic north (which is near the geographic south). This 11° offset is the magnetic declination. If a question asks where a compass needle points, always select 'magnetic north,' not 'geographic north.' **Trap 2: Assuming Non-Magnetic Materials Block Magnetism.** Students often think plastic or paper blocks magnetic fields. Wrong. Magnetic field lines pass through non-magnetic materials unimpeded. If a question offers 'surround with copper to block the field,' eliminate it immediately. Only ferromagnetic shielding (mu-metal) can redirect fields. **Trap 3: Misidentifying the Cause of Magnetism.** Test makers love the option 'electrical conductivity determines magnetism.' Copper is an excellent conductor but non-magnetic. Iron is ferromagnetic (domains) regardless of conductivity. Don't confuse electric properties with magnetic properties. **Trap 4: Breaking a Magnet Destroys It.** Newer students think breaking a magnet ruins it. False. Each piece becomes a complete magnet with its own north and south poles. If a question states 'breaking a magnet makes it non-magnetic,' it's a trap. **Trap 5: Heating Always Removes Magnetism Permanently.** Students think heating always destroys a magnet forever. Actually, below the Curie temperature, magnetism returns upon cooling if domains realign. Above Curie temperature, domains randomize temporarily; cooling may restore magnetism if cooling is controlled. Only extreme heating (above Curie point, then rapid cooling without alignment) causes permanent loss.

Solving 30 MCQs in a timed exam requires strategy. Here's a proven approach: **Phase 1: Quick Scan (2 minutes).** Glance through all 30 questions. Identify straightforward factual questions (e.g., 'which is a magnetic material?') vs. complex assertion-reason pairs. Mark easy ones mentally. **Phase 2: Solve Easy Questions First (12–15 minutes).** Tackle all Easy-level MCQs first (Q1–Q10). These are recall-based and build confidence. Target 90–95% accuracy. Spend 1–1.5 minutes per question maximum. Avoid second-guessing. **Phase 3: Tackle Medium Questions (15–18 minutes).** Move to Medium-level MCQs (Q11–Q20). These require conceptual thinking but are shorter to solve than hard ones. Read each question fully, eliminate obviously wrong options, then reason through remaining two. Spend 1.5–2 minutes per question. **Phase 4: Hard / Assertion-Reason (12–15 minutes).** These are time-hungry. Read the assertion first, verify it true/false. Then evaluate the reason. Match to the correct option template: (A) both true, reason explains assertion, (B) both true, reason doesn't explain, (C) assertion true, reason false, (D) both false. Spend 2–2.5 minutes per question. **Phase 5: Review & Guess (3–5 minutes).** If time remains, review flagged questions and educated guesses. Never leave blanks—at 25% chance on a guess, you gain expected points. **Time Allocation Table:** - Easy (Q1–Q10): 12 min ÷ 10 = 1.2 min/Q - Medium (Q11–Q20): 16 min ÷ 10 = 1.6 min/Q - Hard (Q21–Q30): 14 min ÷ 10 = 1.4 min/Q - Buffer: 5 min - **Total: 47 minutes for 30 questions.** **Pro Tips:** 1. Skip + return: If stuck >90 seconds, skip and return if time permits. 2. Keyword spotting: In assertion-reason, highlight 'always,' 'never,' 'sometimes'—these change meaning. 3. Elimination: Cross out 2 obviously wrong options first—improves 50-50 odds to 75% on remaining two. 4. Curie temperature, magnetic declination, and Curie point are high-frequency hard question anchors—master these concepts. 5. Simulate: Practice 10 timed quizzes before the real exam to calibrate your pace.