6b-Magnetism Flashcards
Q: What is a magnetic field?A:
A magnetic field is the region around a magnet where magnetic forces act.
Q: How can magnetic fields be represented?
A: Magnetic fields are represented using field lines, which:
Point from North to South outside a magnet.
Are closer together where the field is stronger.
Never cross each other.
What is the Earth’s magnetic field?
A: The Earth has a magnetic field similar to a bar magnet, with a magnetic South Pole near the geographic North Pole.
Q: What materials are magnetic?
A: The main magnetic materials are:
Iron
Cobalt
Nickel
Q: What is the difference between hard and soft magnetic materials?
A:
Hard magnetic materials (e.g., steel) remain magnetized permanently.
Soft magnetic materials (e.g., pure iron) can be magnetized and demagnetized easily.
How can you make a magnet?
A:
By stroking a magnetic material with a permanent magnet.
By placing the material in a strong magnetic field.
By using an electric current (electromagnets).
Q: How can you demagnetize a magnet?
A:
By heating it.
By hammering it.
By placing it in an alternating current (AC) coil.
Q: What is an electromagnet?
A: An electromagnet is a coil of wire with a current flowing through it, creating a magnetic field.
Q: How can you increase the strength of an electromagnet?
A:
Increase the current.
Increase the number of coils.
Use a soft iron core inside the coil.
Practical: Investigating Magnetic Fields
Using Iron Filings to Show a Magnetic Field
Method: Place a magnet under a piece of paper and sprinkle iron filings.
Observation: The filings align along the magnetic field lines.
Practical: Investigating Magnetic Fields
Using a Compass to Trace Field Lines
Using a Compass to Trace Field Lines
Method: Place a compass near a bar magnet and mark the direction of the needle.
Observation: The compass traces the field lines from North to South.
