Electricity Flashcards

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1
Q

What is an electric current?

A

The flow of electrical charge

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2
Q

What is current measured in?

A

Amps

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3
Q

What is electric charge measured in?

A

Coulombs

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4
Q

What is the resistance?

A

A measure of how it resists the flow of charge

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5
Q

What happens when the resistance is high?

A

Difficult for charge to flow
Lower the current

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6
Q

What is resistance measured in?

A

Ohms

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7
Q

What does potential difference tell us?

A

The difference in electrical potential from one point in a circuit to another

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8
Q

What can potential difference be thought of as?

A

Electrical push

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9
Q

What happens if the potential difference is bigger across a component?

A

The flow of charge is greater through the component
The bigger the current

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10
Q

What is potential difference measured in?

A

Volts

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11
Q

What do potential difference-current graphs show?

A

The relationship between potential difference and current for any component

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12
Q

What is an ohmic conductor?

A

A resistor in which the current is directly proportional to the potential difference at a constant temperature

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13
Q

How will current through a diode?

A

In one direction

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14
Q

What happens as the resistance of a thermistor decreases?

A

The temperature increases

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15
Q

What happens as light intensity increases in LDRs?

A

The resistance decreases

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16
Q

What happens as the current through a filament lamp increases?

A

The temperature increases

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17
Q

What are the two types of circuit?

A

Series
Parallel

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18
Q

What does the power of a device depend on?

A

The potential difference across it and the current flowing through it

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19
Q

What is a direct current?

A

Has a potential difference that is always positives or always negative
Used in batteries

20
Q

What is an alternating current?

A

Has a potential difference that alternates from positive to negative
Used in mains electricity

21
Q

What V and Hz used in the UK mains?

A

230V, 50Hz

22
Q

What colour is the live wire?

A

Brown

23
Q

What colour is the neutral wire?

A

Blue

24
Q

What colour is the earth wire?

A

Green and Yellow stripes

25
Q

What voltage goes through the live wire?

A

230V

26
Q

What voltage goes throught the neutral and earth wire?

A

0V

27
Q

What does the live wire do?

A

Carries current to the appliance

28
Q

What does the neutral wire do?

A

Carries current away from the appliance

29
Q

What does the earth wire do?

A

Stops the exterior of the appliance becoming live

30
Q

What is power?

A

The rate at which energy is transferred or work is done

31
Q

What is efficiency?

A

The ratio of useful energy out to total energy in

32
Q

How do you increase the efficiency of an energy transfer?

A

Reduce the amount of waste energy

33
Q

What is the national grid?

A

A system of cables and transformers linking power stations to homes and businesses

34
Q

What does the power station do?

A

Transfers the energy supply into electrical energy

35
Q

What do step up transformers do?

A

Increase potential difference from the power station to the transmission cables

36
Q

What do transmission cables do?

A

Transfer the electricity

37
Q

What do step down transformers do?

A

Reduce the potential difference

38
Q

What happens when insulating materials are rubbed together?

A

They become electrically charged

39
Q

What does the friction do when two insulating materials are rubbed together?

A

Moves negatively charged electrons from one material to another

40
Q

What is an object with no conducting path referred to as?

A

Isolated object

41
Q

What happens as the charge of an isolated object increases?

A

The potential difference between the object and the earth increases

42
Q

What kind of force is an electro static force?

A

Non-contact

43
Q

What can electrostatic forces be?

A

Attraction or repulsion

44
Q

What happens when two objects have the same charge?

A

The repel

45
Q

What happens when two objects have a different charge?

A

They attract

46
Q

What does a charged object create?

A

A electric field around itself

47
Q

What does the strength of an electric field depend on?

A

The distance from the object
The amount of charge