Basics & Definitions
Q1. Define a magnet.
A magnet is an object that attracts magnetic materials like iron and produces a magnetic field around it.
Q2. What are magnetic poles?
Magnetic poles are the ends of a magnet where the magnetic force is strongest — called North and South poles.
Q3. State the rule of attraction and repulsion between poles.
Like poles repel each other while unlike poles attract each other.
Q4. What is meant by magnetic field?
Magnetic field is the space around a magnet where its magnetic force can be detected and where it can influence magnetic materials.
Q5. How do field lines show direction?
Field lines are drawn with arrows from the North pole to the South pole to indicate the direction of the magnetic field outside a magnet.
Magnetic & Non-magnetic Materials
Q6. Give three examples of magnetic materials.
Iron, nickel and cobalt are common magnetic materials.
Q7. Give three examples of non-magnetic materials.
Wood, plastic and glass are non-magnetic materials.
Q8. Why are some metals non-magnetic?
Some metals lack the internal atomic structure (alignment of domains) that responds to magnetic fields, so they are not attracted to magnets.
Q9. Is a steel pin magnetic? Explain briefly.
Yes, steel contains iron and is usually magnetic; a pin made of steel will be attracted to a magnet.
Q10. Can a magnet attract a wooden object? Why or why not?
No, wood is non-magnetic and does not respond to magnetic fields, so a magnet will not attract it.
Poles & Behaviour
Q11. What happens if you break a bar magnet into two pieces?
Each piece becomes a smaller magnet with its own North and South poles.
Q12. Can isolated magnetic monopoles be made by cutting a magnet?
No, cutting a magnet does not produce a single pole; each part still has both poles.
Q13. Describe how two magnets interact when opposite poles face each other.
Opposite poles attract, so the magnets will pull towards each other and may stick together.
Q14. Describe the interaction when like poles face each other.
Like poles repel, so the magnets push away from each other and cannot be brought close easily.
Q15. Which pole of a magnet points towards geographic north when used as a compass?
The north-seeking pole (commonly called the north pole of the magnetized needle) points towards geographic north.
Field Lines & Visualization
Q16. How can iron filings be used to show magnetic field lines?
Sprinkle iron filings on a paper placed over a magnet; the filings align along the field lines and show the field pattern.
Q17. Why do field lines never cross?
Field lines represent direction of magnetic force at each point; crossing would imply two directions at one point, which is impossible.
Q18. What does a dense concentration of field lines indicate?
A dense concentration of lines indicates a stronger magnetic field in that region.
Q19. How do field lines behave inside a magnet?
Inside a magnet, field lines run from the South pole to the North pole, completing continuous loops.
Q20. How would field lines look between two opposite poles close together?
Field lines would be denser and connect from the North pole of one magnet to the South pole of the other showing strong attraction.
Temporary & Permanent Magnets
Q21. Define a permanent magnet with an example.
A permanent magnet retains its magnetism over a long time; e.g., a refrigerator magnet or a magnetized steel needle.
Q22. Define a temporary magnet with an example.
A temporary magnet behaves like a magnet only when placed in a magnetic field; e.g., a paper clip becomes magnetic when touching a magnet.
Q23. How can you make a simple magnet at home?
Stroke a steel needle or a small iron object repeatedly in one direction with a strong magnet to align its domains and make it magnetic.
Q24. What are some ways to demagnetize a magnet?
Heating, hammering, or subjecting it to alternating or reverse magnetic fields can demagnetize a magnet.
Q25. Why are keepers used for storing magnets?
A keeper (soft iron bar) across the poles reduces the loss of magnetism by providing a closed path for magnetic lines, protecting the magnet's strength.
Experiments & Practicals
Q26. Outline steps to test which objects are magnetic.
Bring a magnet near various objects (pins, coins, wood, plastic) and note which items get attracted; those are magnetic.
Q27. What observation confirms that an object is magnetic?
If the object sticks to the magnet or moves toward it, it is magnetic.
Q28. How should you arrange the setup for the iron filings experiment to avoid mess?
Place the magnet on a tray and the paper over it; conduct the experiment on the tray so filings are contained for easy cleanup.
Q29. What safety measures are important during magnet experiments?
Keep filings away from eyes and mouth, avoid bringing strong magnets near electronics and credit cards, and supervise children during experiments.
Q30. Why might a teacher ask for conclusion after an experiment?
A conclusion summarizes what was observed and links the result to the scientific principle being tested, showing understanding.
Applications & Technology
Q31. How does a compass work?
A compass contains a small magnetized needle that aligns with Earth's magnetic field, showing direction (north-south).
Q32. Why are magnets important in electric motors?
Magnets interact with electric currents to create forces that produce rotation, which is the working principle of motors.
Q33. Give two everyday uses of magnets.
Fridge magnets for holding notes and magnetic latches for cabinet doors.
Q34. How do speakers use magnets to produce sound?
Magnets interact with current in a coil attached to the speaker cone, causing it to vibrate and produce sound waves.
Q35. Explain one industrial use of magnets.
Magnetic separators remove ferrous metals from recycled material, improving purity and recovery in recycling plants.
Conceptual & Higher Order
Q36. Why don't non-magnetic materials show magnetism even near a strong magnet?
Their internal atomic structure and magnetic domains do not align to produce net magnetism in presence of an external field.
Q37. Explain briefly why field lines form closed loops.
Magnetic field lines have no beginning or end; they complete continuous closed paths from North to South outside and South to North inside the magnet.
Q38. Why is Earth's magnetic field important for navigation?
Earth's magnetic field provides a reference direction (north-south) that compasses use to determine direction for navigation.
Q39. How can magnets be used to separate materials?
Using magnets to attract and remove magnetic components (like iron) from a mixture leaves behind non-magnetic parts for separation.
Q40. What effect does temperature have on magnetism?
Heating can disturb the alignment of domains and reduce or remove magnetism; some materials lose magnetism at high temperatures.
Quick Revision & Exam Tips
Q41. What should you include when answering an experiment question in exam?
Mention materials, method (steps), observations, and a brief conclusion linking to the principle.
Q42. How to draw magnetic field lines for a bar magnet in exam?
Draw curved lines starting from the North pole and ending at the South pole outside the magnet; show arrows and label poles.
Q43. Give a short answer: Why do magnets lose strength over time?
Exposure to heat, strong impacts, or opposing magnetic fields can disrupt domain alignment and reduce magnet strength over time.
Q44. What is a magnetic compass needle made of?
A magnetic compass needle is usually a small magnetized piece of metal (often steel) balanced to rotate freely and align with Earth's field.
Q45. How can you test whether a coin is magnetic?
Bring a magnet close to the coin; if it is attracted, the coin contains magnetic metal like iron or steel.
Q46. Why should magnets be kept away from electronic devices?
Strong magnets can erase or damage magnetic storage (like old hard drives) and can interfere with sensitive electronic components.
Q47. Suggest a classroom demonstration to show repulsion between poles.
Hold two bar magnets with like poles facing; show how they push apart and explain that like poles repel.
Q48. How does a magnetic clasp on jewelry work?
Two magnets or a magnet and metal attract and hold the clasp closed by magnetic force until separated.
Q49. Briefly describe the role of magnets in MRI machines (general idea).
MRI uses very strong magnets to align atomic particles in the body; signals from these alignments are used to create internal images (medical imaging uses highly controlled magnetism).
Q50. Write one final revision tip for this chapter.
Practice drawing field lines, perform simple experiments safely, and memorise key definitions and examples for quick recall in exams.