Topic 7 - Magnetism and Electromagnetism Flashcards
(23 cards)
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
Thumb - Force
Index Finger - Mag Field
Middle Finger - Current
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 Poles
The regions of a magnet where the magnetic forces are at their
strongest.
Magnetic Materials
Iron, steel, cobalt and nickel.
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.
