Magnetism and Electromagnetism Assessment

If you break a bar magnet in half, what happens to the magnetic poles?

• Each half loses one pole
• Each half becomes a monopole
• Each half gets new N and S poles
• The poles disappear completely

Why do magnetic field lines never cross each other?

• Because they represent unique paths of magnetic force
• Because magnets repel each other
• Because they only flow North to South
• Because they are just drawing conventions

What makes steel a 'magnetically hard' material compared to iron?

• Steel is physically harder
• Steel retains magnetism permanently
• Steel is more difficult to magnetize
• Steel conducts electricity better

If magnetic field lines are very close together, what does this indicate?

• Weak magnetic field
• Strong magnetic field
• Uniform magnetic field
• No magnetic field

Why can't magnetic monopoles exist naturally?

• Magnetic field lines must form closed loops
• Monopoles would be too powerful
• Monopoles would cancel each other
• It's just a coincidence

A student places two magnets end to end and they snap together. What can you conclude?

• The ends must be the same poles
• The ends must be opposite poles
• The magnets are too strong
• The magnets are defective

Which factor does NOT affect the strength of an electromagnet?

• Number of coil turns
• Type of core material
• Color of the wire
• Amount of current

Why is soft iron preferred for electromagnet cores?

• It's cheaper than other materials
• It becomes temporarily magnetic easily
• It's physically softer
• It conducts electricity better

How would doubling the current through an electromagnet affect its magnetic field strength?

• Make it twice as strong
• Make it four times stronger
• Make it half as strong
• Have no effect

What determines the direction of force in the motor effect?

• Fleming's Left-Hand Rule
• The Right-Hand Grip Rule
• Magnetic pole direction only
• Current direction only