Generating ElectricityOxford AQA IGCSE Physics: Flashcards

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Define the generator effect.

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Define the generator effect.: A potential difference is induced across a conductor when it moves relative to a magnetic field, or is in a changing magnetic field.
When is a pd induced across a coil using a permanent magnet?: When the magnet is moved into or out of the coil, or the coil is moved relative to the magnet.
What must be true for an induced pd to cause a current to flow?: The conductor must be part of a complete circuit.
What does the field of an induced current do in relation to the magnet producing it?: It opposes the field of the permanent magnet.
What happens if you reverse the direction of motion of the magnet?: The polarity of the induced pd and the direction of the induced current are reversed.
Name four factors that increase the size of an induced pd.: Increasing speed of movement, using a stronger magnetic field, more turns on the coil, and a larger coil area.
What type of current does an alternator generate?: Alternating current (ac).
What type of current does a dynamo generate?: Direct current (dc).
How does a pd-time graph for an alternator differ from a dynamo?: The alternator's graph is a wave that regularly reverses direction; the dynamo's graph stays on one side of the axis.
What do power stations use to turn coils of wire between magnets?: Turbines.
If you reverse the polarity of the magnet used to induce a current, what happens?: The direction of the induced current is reversed.