7: Magnetism and Electromagnetism Flashcards
Alternator:
A device that makes use of the generator effect to generate alternating current.
Attraction:
Opposite poles will experience a force of attraction, meaning they will experience a force towards each other. The force between a magnet and magnetic material is always one of attraction.
Current-Carrying Wires:
When current flows through a wire, a magnetic field is generated around it. The strength of the field is dependent on the magnitude of the current and the distance from the wire.
Dynamo:
A device that makes use of the generator effect to generate direct current.
Electric Motor:
A current-carrying coil of wire in a magnetic field. The two sides of the coil that are perpendicular to the magnetic field experience forces in opposite directions, causing rotation.
Electromagnet:
A solenoid with an iron core.
Fleming’s Left-Hand Rule:
A rule used to determine the orientation of the force (thumb), current (second finger) and magnetic field (first finger) when a current carrying wire is placed in a magnetic field (motor effect).
Generator Effect:
When there is relative motion between an electrical conductor and a magnetic field, a potential difference will be induced across the ends of the conductor. A current will flow if this conductor is part of a complete circuit.
Induced Magnet:
A material that becomes a magnet when it is placed in an existing magnetic field, but loses its magnetism quickly once it is removed. Induced magnetism always produces attractive forces
Magnetic Compass:
A device containing a small bar magnet that points in the direction of the Earth’s magnetic field.
Magnetic Field Lines:
Lines representing the strength and direction of a magnetic field. The field line direction at any point is in the direction that a force would act on another north pole if placed at that point.
Magnetic Field:
The region around a magnet in which another magnet or magnetic material will experience a force.
Magnetic Materials:
Iron, steel, cobalt and nickel.
Magnetic Poles:
The regions of a magnet where the magnetic forces are at their strongest.
Microphone:
A device that uses the generator effect to convert the pressure variations of sound waves into variations in the electrical current of a circuit.
Motor Effect:
When a current-carrying wire is placed in a magnetic field, a force will be experienced between the wire and the magnet responsible for the field.
Permanent Magnet:
A magnet that produces its own magnetic field.
Repulsion:
Like-poles will experience a force of repulsion, meaning they will experience forces in opposite directions.
Solenoid:
A wire wrapped into the shape of a coil, that has a strong and uniform magnetic field inside of it. The solenoid’s magnetic field strength can be increased by adding an iron core.
Step-Down Transformer:
A transformer that has a smaller potential difference in the secondary coil than in the primary core.
Step-Up Transformer:
A transformer that has a larger potential difference in the secondary coil than in the primary core.
Tesla:
The unit of magnetic flux density.
Transformer:
An iron core with a primary and secondary coil of wire wound around opposite ends.
