# U2 Physics

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What can Ohm's Law be used to find?
The resistance of a component
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What does an ammeter find?
The current
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What does a voltmeter find?
The amount of volts in a certain area in a circuit
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How do you calculate resistance?
Voltage/Current
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What are some examples of Ohmic conductors?
copper wires, filament bulbs, resistor
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What is a Ohmic conductor?
An Ohmic conductor is a component that obeys Ohm's Law and where the current and voltage are proportional.
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Why is Ohm's Law not valid when the temperature of the conductor increases?
The ions in the component vibrate, making it hard for the electrons to pass through and more collisions to take place.
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What is a series circuit?
A simple circuit with only one loop.
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What is a parallel circuit?
A parallel is a circuit with two or more loops It will have a junction(s) where the current splits.
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What effect do parallel circuits have on resistance?
They decrease the resistance
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Is the current the same in all the parts of a parallel circuit? Why?
No. Because the current splits up.
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How does the resistance of a series circuit change when you add more resistors?
The reistance increases, therefore the current decreases
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How do you connect ammeters and voltmeters to a circuit?
Ammeters into the circuit and voltmeters out of the circuit.
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What is resistance?
Resistance is the fow of electric current through the most conductor. Collisions between ions and electrons
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What is a superconductor?
A substance capable of becomin superconducting at sufficiently low temperatures
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Why do some materials have no resistance
Cool, less vibrations of ions so more electron pathways
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What are the two different types of electric current?
AC (alternating current) & DC (direct current)
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What does an oscilloscope do?
Shows how the voltage varies with time
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What does the voltage of an AC current do?
Follows a repeated pattern
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What does the voltage of a DC current do?
The voltage of a DC supply is steady and is always in the same direction (it doesnt cross the axis)
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What is frequency
The number of waves a second.
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What type of electricity is provided by a battery?
DC (direct current)
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Describe the electricity that comes out of a wall socket in the UK
AC, 50HZ, 230 volts
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What are the three types of wire?
Live, Earth, Neutral
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What does the neutral wire do?
Completes the circuit
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What does the live wire do?
Carries high voltage
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What does the Earth wire do?
Creates safety
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What is a fuse?
A safety device that melts when too much current flows through, stopping the electricty flowing
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## Other cards in this set

### Card 2

#### Front

What does an ammeter find?

The current

### Card 3

#### Front

What does a voltmeter find?

### Card 4

#### Front

How do you calculate resistance?

### Card 5

#### Front

What are some examples of Ohmic conductors?