7.3 induced potential Flashcards
What happens when an electrical
conductor moves relative to a magnetic
field?
A potential difference is induced across
the ends of the conductor.
What is the requirement for an induced potential
difference to cause a current flow?
The conductor must form a closed loop
or be part of a complete circuit.
What can be said about the direction of
the magnetic field produced by an
induced current?
● The direction of the field is such that it
opposes the change that induced the
current
● This change is either the movement of
the conductor or a change to the field
What are two ways that the generator
effect is used to generate different types
of current?
● In an alternator to produce
alternating-current
● In a dynamo to produce direct-current
What electromagnetic effect does a
microphone take advantage of and how?
● The generator effect
● It converts the pressure variations in
sound waves into alternating current in
a circuit
Describe the makeup of a basic
transformer.
A primary coil and a secondary coil of
wire wrapped around an iron core.
Why is iron used as the core for a
transformer?
It is easily magnetised
Explain how a transformer works.
● An alternating current flows through the
primary coil
● This induces a changing magnetic field in
the core
● This changing magnetic induces a current
to flow in the secondary coil
Why must the current flowing through the
primary coil of a transformer be
alternating?
● For current to be induced in the secondary
coil, the magnetic field in the core must be
continuously changing
● For the magnetic field to be changing, the
current in the primary coil must be alternating
What can be said about the electrical power input
and output of a 100% efficient transformer?
What can be said about the electrical power input
and output of a 100% efficient transformer?
