Exploring Magnets – MCQs with Answers and Explanations
Chapter 4: Exploring Magnets — 40 Multiple Choice Questions
- Objective-type MCQs for quick concept checks (1 mark each).
- Short/Long answer and diagram-based questions testing experiments and applications.
- Practical assessment of experiments: materials, method, observations, conclusions.
Basics of Magnets
Explanation: Wooden objects are non-magnetic; magnets are usually made of magnetic materials like iron, steel, or specially processed alloys.
Explanation: Every magnet has two poles — North and South. Even if broken, each piece will have both poles.
Explanation: Like poles (N–N or S–S) push away from each other; unlike poles (N–S) attract.
Explanation: Iron is attracted to magnets; materials like plastic, glass and wood are non-magnetic.
Explanation: Wooden objects are non-magnetic and will not be attracted by a magnet.
Magnetic Field & Field Lines
Explanation: By convention, magnetic field lines outside a magnet are drawn from the North pole to the South pole.
Explanation: Iron filings align along field lines, making the otherwise invisible field visible as a pattern.
Explanation: Field is strongest at the poles, so field lines are denser there.
Explanation: Outside the magnet, field lines run from North to South, not from South.
Explanation: Each small piece becomes a tiny magnet and aligns with the local magnetic field, revealing the pattern.
Poles & Interaction
Explanation: Like poles repel each other; north-north pushes away.
Explanation: Cutting a magnet creates two smaller magnets, each with North and South poles.
Explanation: The pole of a compass needle or magnet that points towards geographic north is referred to as the north-seeking pole.
Explanation: If an object is attracted to a magnet, it is considered magnetic (contains ferrous material).
Explanation: Opposite poles (N–S) attract; this is used in many magnetic applications.
Magnetic & Non-magnetic Materials
Explanation: Copper is non-magnetic while iron and steel items are magnetic.
Explanation: Steel contains iron and is commonly magnetic; brass and aluminium are non-magnetic alloys.
Explanation: The paper clip acts like a magnet only while under the influence of the strong magnet; it loses magnetism later.
Explanation: A keeper (soft iron bar) across the poles gives a path for magnetic flux, reducing loss of magnetism.
Explanation: Heating can disrupt domain alignment; high temperatures may demagnetize a magnet.
Experiments & Practicals
Explanation: Denser patterns at poles indicate stronger magnetic fields there.
Explanation: Heating is unnecessary and may damage the magnet; the experiment uses paper, filings, and tapping.
Explanation: Recording attraction and distance helps understand relative magnetic strength and material response.
Explanation: A tray helps contain the small filings and prevents mess and loss, making cleanup simple and safe.
Explanation: Iron filings can harm eyes and can stick to electronic devices, potentially causing damage; handle carefully and clean up properly.
Applications of Magnets
Explanation: A compass has a magnetised needle that aligns with Earth's magnetic field to indicate direction.
Explanation: Magnets have many uses at home — holding notes, producing sound in speakers, and creating motion in motors.
Explanation: Magnetic separators attract iron and steel from mixed waste, enabling recycling of these materials.
Explanation: Interaction between magnets and current-carrying coils produces forces that make motor parts rotate.
Explanation: MRI (Magnetic Resonance Imaging) uses very strong magnets to generate images of the body's internal structures.
Safety & Care
Explanation: Strong magnets can erase or damage magnetic strips and storage media (e.g., credit cards, old hard drives).
Explanation: Multiple swallowed magnets can attract each other through intestinal walls, causing serious injuries requiring medical attention.
Explanation: Keepers reduce stray fields and help preserve magnet strength; spacers prevent magnets from snapping together and damaging each other.
Explanation: Magnets can disturb orientation sensors and compasses in phones and sometimes affect components; keep them apart.
Thinking, Application & Revision
Explanation: Magnetic fields penetrate non-magnetic materials; the force decreases with distance but can act through such barriers.
Explanation: Nearby strong magnets create local fields that override Earth's weaker field in that region.
Explanation: The magnet and coil interaction creates movement of the speaker cone or headphone diaphragm, producing sound.
Explanation: CBSE expects clear, structured answers for practical questions including materials, steps, observations and a conclusion.
Explanation: Drawing field lines and revising definitions helps understand concepts and score well in exams.
Explanation: Chapter 4 focuses on magnets, their properties, magnetic fields, experiments, and real-life applications.
