Magnetism Flashcards
What are the two poles of a magnet?
North and South.
Name three magnetic materials.
Iron, nickel, cobalt.
What is the difference between a permanent magnet and an induced magnet?
Permanent magnets produce their own magnetic field; induced magnets become temporary magnets in a magnetic field.
What direction do magnetic field lines point outside a magnet?
From the North pole to the South pole.
Why does a compass needle align with Earth’s magnetic field?
The Earth’s core generates a magnetic field
What is an electromagnet?
A coil of wire (solenoid) with an iron core that becomes magnetic when current flows.
How can you increase the strength of an electromagnet?
Increase current, add more coil turns, or use a soft iron core.
What does the right-hand grip rule determine?
The direction of the magnetic field around a current-carrying wire (thumb = current
What is the motor effect?
A force experienced by a current-carrying conductor in a magnetic field.
What does Fleming’s left-hand rule predict?
Direction of force in the motor effect (Thumb = Force, First finger = Field, Second finger = Current).
How can you increase the force on a wire in the motor effect?
Increase current, use a stronger magnet, or increase conductor length in the field.
Give two applications of electromagnets.
Relays and electric motors (or circuit breakers/loudspeakers).
Describe the magnetic field around a straight current-carrying wire.
Concentric circles weakening with distance from the wire.
What is the magnetic field inside a solenoid similar to?
A bar magnet (with distinct North and South poles).
Why are electromagnets used in scrap yards?
To lift/drop magnetic materials by switching the current on/off.
How does a permanent magnet differ from an electromagnet?
Permanent magnets retain magnetism; electromagnets are temporary (only with current).
What factors affect the force in the motor effect?
Current, magnetic field strength, and length of conductor in the field.
How does a compass show magnetic field direction?
The needle aligns with field lines
