Magnetism Flashcards
What is a magnetic field?
A region around a magnet where magnetic forces are experienced.
What are magnetic poles?
The two ends of a magnet:
• North pole
• South pole
Opposite poles attract, like poles repel.
What material is attracted to magnets?
Magnetic materials such as iron, nickel, and cobalt are attracted to magnets.
How can you map the magnetic field of a magnet?
By using iron filings or a compass. The filings align along the magnetic field lines, showing their direction.
What is the direction of magnetic field lines?
Magnetic field lines point from the north pole to the south pole outside the magnet, and from south to north inside the magnet.
What happens when you cut a magnet in half?
You create two smaller magnets, each with a north and south pole.
What is an electromagnet?
A magnet created by passing an electric current through a coil of wire. The magnetism is temporary and can be switched on or off.
What is an electromagnet?
A magnet created by passing an electric current through a coil of wire. The magnetism is temporary and can be switched on or off.
How can you increase the strength of an electromagnet?
- Increase the number of coils in the wire.
- Increase the current passing through the wire.
- Use a soft iron core inside the coil.
What is the right-hand rule for current-carrying conductors?
When you hold a current-carrying wire with your right hand, the direction of your fingers shows the direction of the magnetic field around the wire. The thumb points in the direction of the current.
What is the force on a current-carrying wire in a magnetic field?
A force is exerted on the wire when it is at an angle to the magnetic field. The force is greatest when the wire is at 90° to the field.
What is Fleming’s Left-Hand Rule?
This rule is used to find the direction of the force on a current-carrying wire in a magnetic field:
• Thumb = Force
• First finger = Magnetic Field
• Second finger = Current
What is the motor effect?
The phenomenon where a current-carrying conductor in a magnetic field experiences a force. This principle is used in electric motors.
What factors affect the size of the force on a current-carrying wire in a magnetic field?
- Strength of the magnetic field
- Current passing through the wire
- Length of the wire in the magnetic field
- The angle between the magnetic field and the current-carrying wire (maximum at 90°).
What is the purpose of an armature in an electric motor?
The armature is the rotating part of the motor that turns when a current is passed through it in a magnetic field.
What is electromagnetic induction?
The process of generating an electric current by changing the magnetic field around a conductor.
How can you increase the induced voltage in electromagnetic induction?
- Increase the speed of movement between the conductor and the magnetic field.
- Use a stronger magnetic field.
- Increase the number of coils in the wire.
What is a generator?
A device that uses electromagnetic induction to convert mechanical energy into electrical energy.
