IGCSE Physics- Electricity and Magnetism

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What metals can a permanent magnet be made out of?
Iron, Nickel, Cobalt (and Steel)
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If these metals have not been turned into magnets but are in the magnetic field of a magnet, will they be attracted to it?
Yes
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What is this called?
Induced magnetism
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You can only prove an object is a magnet if it _______ another magnet
You can only prove an object is a magnet if it repels another magnet
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In which direction do the magnetic field lines go? North to South or South to North?
NORTH to SOUTH
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When an electric current flows in a wire it creates what around the wire?
A magnetic field
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How do you make an electromagnet stronger? (3 points)
1. More turns in the coil, 2. Wrapping the wire around and iron core, 3. Increasing the current in the coil
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What is a relay?
An electrically operated switch
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Voltage is produced when a magnet moves inside a coil of wire, what is this called?
Electromagnetic induction
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How do you increase electromagnetic induction? (3 points)
1. Add more turns to the coil, 2. Increase the strength of the magnet, 3. Move the magnet faster
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What is a simple electric motor made of?
A coil of wire that can move between two opposite poles (magnets)
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Why must the direction of the current be reversed every half turn?
Otherwise the coil of wire wouldn't turn any further
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What part of the motor is responsible for this?
Split ring/commutator
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How does a generator induce a current? (with a magnet and a coil of wire)
By spinning a magnet inside a coil of wire
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How does a bicycle dynamo work?
The dynamo has a wheel that touches the back tyre. As the bicycle moves, the wheel turns a magnet inside a coil.
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When do you use Fleming's left hand rule and when do you use Fleming's right hand rule?
Left: motors, Right: generators
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thuMb is for?
Movement
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Forefinger is for?
Field (North to South)
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seCond finger is for?
Current (+ to -)
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Does a generator produce AC or DC?
AC because as the magnet/coil is rotated, the direction of the current is reversed EVERY HALF TURN
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The size of the induced voltage can be increased by: (3 points)
1. Rotating the magnet/coil faster, 2. Using a stronger magnet, 3. More turns in the coil
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Is mains current AC or DC?
AC and 230V
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Transformers are used to increase/decrease what? e.g. current...voltage
Voltage
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A transformer consists of ___ coils of wire around a metal ____
A transformer consists of TWO coils of wire around a metal CORE
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If the PRIMARY coil has more turns than the SECONDARY coil, is the voltage being increased or reduced?
Reduced
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When a _______ flows through a wire some energy is lost as ____.
When a CURRENT flows through a wire some energy is lost as HEAT
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To reduce the _______ (and therefore the heat loss) the National Grid transmits __________ at a low _______
To reduce the CURRENT (and therefore the heat loss) the National Grid transmits ELECTRICITY at a low CURRENT
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How do they lower the current? and what device do they use?
Increase the voltage using a step-up transformer
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What is an equation that links electrical power, voltage and current?
(elecrtical) power = voltage x current
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Dangers of UV?
Cancer, UV burns, blindness
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Dangers of infrared?
Burns
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Dangers of microwaves?
Internal heating of body tissues
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Dangers of BOTH X-rays and Gamma rays?
Cell mutation, Cancer, Kills cells
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Other cards in this set

Card 2

Front

If these metals have not been turned into magnets but are in the magnetic field of a magnet, will they be attracted to it?

Back

Yes

Card 3

Front

What is this called?

Back

Preview of the front of card 3

Card 4

Front

You can only prove an object is a magnet if it _______ another magnet

Back

Preview of the front of card 4

Card 5

Front

In which direction do the magnetic field lines go? North to South or South to North?

Back

Preview of the front of card 5
View more cards

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