Simple Magnetism And Magnetic FieldsCopy
1. Which material is best for making temporary magnets?
A) Steel
B) Iron
C) Copper
D) Cobalt
2. Which property best distinguishes soft magnetic materials?
A) Cannot be magnetised
B) Retain magnetism permanently
C) Easily magnetised and demagnetised
D) Do not attract magnetic materials
3. Which experiment best shows magnetic field lines?
A) Using a voltmeter
B) Sprinkling iron filings on paper over a magnet
C) Dipping metal in acid
D) Using a thermometer
4. In a bar magnet, field lines emerge from:
A) South to North
B) Center to ends
C) North to South
D) Randomly
5. Two bar magnets are placed with like poles facing. What happens?
A) They attract
B) They rotate
C) They repel
D) Nothing
6. Which of the following is a non-magnetic material?
A) Iron
B) Steel
C) Aluminium
D) Nickel
7. Which of the following is a true statement about magnetic poles?
A) They exist independently
B) North and South poles can be separated
C) They always exist in pairs
D) South pole is stronger
8. Which method is least effective for showing magnetic field lines?
A) Iron filings
B) Compass tracing
C) Thermographic imaging
D) Plotting compasses
9. The direction of magnetic field at a point is defined as:
A) From S to N
B) Direction of force on S pole
C) Tangent to field line
D) Direction of force on N pole
10. What causes a material to become permanently magnetised?
A) Stroking with a plastic rod
B) Placing in alternating current
C) Heating in sunlight
D) Strong, steady DC magnetic field
11. Which of the following is an example of induced magnetism?
A) A magnet attracting wood
B) Iron nail becoming magnetised near a bar magnet
C) Steel losing magnetism
D) North and south poles separating
12. What happens to a soft iron bar when the external magnetic field is removed?
A) Becomes stronger
B) Remains magnetised
C) Demagnetises
D) Turns into a permanent magnet
13. What is the main advantage of electromagnets?
A) They can’t be switched off
B) Require no current
C) Have permanent polarity
D) Can be turned on/off and strength varied
14. Which of the following would strengthen an electromagnet?
A) Reduce number of coil turns
B) Use air as core
C) Increase current
D) Use thinner wire
15. Which material is commonly used in magnetic shielding?
A) Plastic
B) Steel
C) Aluminium
D) Wood
16. Why are the field lines closer at the poles of a magnet?
A) Weak field
B) Stronger field
C) Reversed polarity
D) Non-uniform shape
17. Magnetic field strength is highest:
A) At the midpoint of a bar magnet
B) Equally everywhere
C) At the poles
D) At neutral points
18. Which pair shows like poles?
A) N–S
B) N–N
C) S–N
D) S–unmagnetised rod
19. A neutral point between two magnets indicates:
A) Maximum attraction
B) Zero field strength
C) Weak repulsion
D) Centre of the magnet
20. A compass placed near a magnet points:
A) Randomly
B) Along a tangent to the field line
C) Toward S always
D) Toward nearest pole
21. Which pole does a compass needle point toward?
A) Magnetic South
B) Electric field source
C) Geographical East
D) Magnetic North
22. What is the core of an electromagnet made of?
A) Aluminium
B) Soft iron
C) Steel
D) Copper
23. Which of the following is most suitable for permanent magnets?
A) Copper
B) Soft iron
C) Steel
D) Lead
24. Heating a magnet generally causes:
A) Stronger field
B) Reverse polarity
C) Demagnetisation
D) No change
25. Stroking a magnetic material repeatedly in the same direction with one pole creates:
A) Alternating field
B) Random magnetism
C) Induced magnetism
D) Permanent magnetism
26. A plotting compass is used to:
A) Measure mass
B) Track temperature
C) Trace magnetic field direction
D) Detect electric field
27. Electromagnets are used in:
A) Plastic packaging
B) Electric bells
C) Water purification
D) Thermostats
28. If the current through an electromagnet is reversed:
A) Field disappears
B) Field doubles
C) Field direction reverses
D) Nothing changes
29. The field inside a solenoid resembles:
A) That of a point charge
B) That of a light bulb
C) That of a bar magnet
D) No field at all
30. Which of the following loses magnetism the quickest?
A) Steel
B) Soft iron
C) Nickel
D) Cobalt
31. Which diagram best represents field lines between two opposite poles?
A) Straight lines not touching
B) Random loops
C) Arrows from N to S forming loops
D) Lines from S to N
32. A magnet attracts:
A) All metals
B) Non-metals
C) Only magnetic materials
D) Insulators
33. Which of the following correctly describes the law of magnetic poles?
A) Opposites repel, likes attract
B) Like poles repel, unlike poles attract
C) North poles attract each other
D) All poles repel
34. How does alternating current affect magnetism in a solenoid?
A) Creates constant polarity
B) Increases field
C) Causes rapid reversal and weakening
D) Has no effect
35. The angle between true north and magnetic north is called:
A) Latitude
B) Polar drift
C) Declination
D) Inclination
1. ✅ B) Iron
Soft iron = easily magnetised and demagnetised → best for temporary magnets
❌ A – Steel retains magnetism → permanent
❌ C/D – Non-magnetic or less magnetic
2. ✅ C) Easily magnetised and demagnetised
That’s the key feature of soft magnetic materials
❌ A – Can be magnetised
❌ B – Applies to hard materials
❌ D – False
3. ✅ B) Sprinkling iron filings on paper over a magnet
Visualises magnetic field lines effectively
❌ A/C/D – Irrelevant tools
4. ✅ C) North to South
Always defined as N → S outside the magnet
❌ A – Inside magnet
❌ B/D – Incorrect descriptions
5. ✅ C) They repel
Like poles always repel
❌ A – Opposites attract
❌ B – Not applicable
❌ D – Physical interaction occurs
6. ✅ C) Aluminium
Aluminium is non-magnetic
❌ A/B/D – All are magnetic
7. ✅ C) They always exist in pairs
Magnetic monopoles don’t exist
❌ A/B – False physics
❌ D – Strength varies but not always south stronger
8. ✅ C) Thermographic imaging
Doesn’t detect magnetic fields
❌ A/B/D – All are valid methods
9. ✅ D) Direction of force on N pole
Standard convention
❌ A – Incorrect
❌ B – S pole force is opposite
❌ C – True but not full definition
10. ✅ D) Strong, steady DC magnetic field
Used in magnetising metals
❌ A – Plastic is non-magnetic
❌ B – AC causes rapid reversal
❌ C – Heating may demagnetise
11. ✅ B) Iron nail becoming magnetised near a bar magnet
Induced magnetism = temporary magnetism due to field
❌ A – Wood is not magnetic
❌ C – Opposite effect
❌ D – Impossible
12. ✅ C) Demagnetises
Soft iron quickly loses magnetism
❌ A – Opposite
❌ B – Applies to hard magnets
❌ D – Misleading
13. ✅ D) Can be turned on/off and strength varied
Main advantage of electromagnets
❌ A/B/C – False or inapplicable
14. ✅ C) Increase current
More current = stronger field
❌ A – Fewer turns = weaker field
❌ B – Air = weak core
❌ D – Doesn’t affect field much
15. ✅ B) Steel
Steel shields against magnetic fields
❌ A/C/D – Non-magnetic
16. ✅ B) Stronger field
Dense lines = higher magnetic field
❌ A – Opposite
❌ C – Irrelevant
❌ D – Not cause
17. ✅ C) At the poles
Ends of magnet have highest field density
❌ A/B/D – Wrong or misleading
18. ✅ B) N–N
Like poles → N–N or S–S
❌ A/C – Opposites
❌ D – Not a pair of poles
19. ✅ B) Zero field strength
Neutral point = cancelling fields
❌ A/C/D – Wrong definitions
20. ✅ B) Along a tangent to the field line
Compass aligns with field
❌ A – Not random
❌ C/D – Misinterpretations
21. ✅ D) Magnetic North
Compass needle is a north pole → attracted to magnetic south (Earth’s magnetic north)
❌ A – Misleading
❌ B/C – Irrelevant
22. ✅ B) Soft iron
Quickly magnetised/demagnetised → ideal core
❌ A/C/D – Poor magnetic properties
23. ✅ C) Steel
Steel = hard → retains magnetism
❌ A/B/D – Unsuitable
24. ✅ C) Demagnetisation
Heat randomises magnetic domains
❌ A/B/D – Unlikely or false
25. ✅ D) Permanent magnetism
Stroking aligns domains permanently
❌ A/B/C – Misinterpretations
26. ✅ C) Trace magnetic field direction
Standard use of plotting compass
❌ A/B/D – Not applicable
27. ✅ B) Electric bells
Electromagnets trigger movement in bells
❌ A/C/D – Not using electromagnets
28. ✅ C) Field direction reverses
Current reversal → reversed polarity
❌ A/B/D – Misconceptions
29. ✅ C) That of a bar magnet
Solenoid field mimics bar magnet
❌ A/B/D – Not true
30. ✅ B) Soft iron
Soft → fast magnetisation and loss
❌ A/C/D – Retain longer
31. ✅ C) Arrows from N to S forming loops
Standard field pattern
❌ A/B/D – Wrong orientation
32. ✅ C) Only magnetic materials
Iron, nickel, cobalt etc.
❌ A – Not all metals
❌ B/D – Not attracted
33. ✅ B) Like poles repel, unlike poles attract
Law of magnetic poles
❌ A/C/D – Misstatements
34. ✅ C) Causes rapid reversal and weakening
AC disrupts steady domain alignment
❌ A/B/D – Not consistent
35. ✅ C) Declination
Angle between true north and magnetic north
❌ A/B/D – Different geophysical terms