# Topic 9 - Electricity and Circuits COMPLETE PK Flashcards Preview

## GCSE Combined Physics (Edexcel) > Topic 9 - Electricity and Circuits COMPLETE PK > Flashcards

Flashcards in Topic 9 - Electricity and Circuits COMPLETE PK Deck (160)
1
Q

1 What word describes materials that electricity will pass through?

A

conductors

2
Q

2 What word describes materials that electricity cannot pass through?

A

insulators

3
Q

3 What components do you need to make a circuit that would make a small torch bulb light up?

A

battery, connecting wires, lamp; switch is optional

4
Q

4 What are the two terminals of an electric cell labelled as?

A

plus and minus

5
Q

5 In an electric circuit with a battery, which of these materials will conduct: copper, wood, salty water?

A

copper and salty water

6
Q

6 Which of these materials are insulators: plastic, metal, air?

A

plastic and air

7
Q

7 What component is used to measure current?

A

ammeter

8
Q

8 What name is given to the negatively charged subatomic particles that cause an electric current?

A

electrons

9
Q

9 Is mains voltage about 15 times, 150 times or 1500 times bigger than the voltage from a battery?

A

10
Q

10 If you connect some cells together in series, what is formed?

A

a battery

11
Q

11 What is the name of a circuit with one path around it and no branches?

A

a series circuit

12
Q

12 What is the name given to a circuit with components in different branches?

A

a parallel circuit

13
Q

13 What is the circuit symbol for a lamp?

A

circle with a cross in it

14
Q

14 What is the circuit symbol for a cell?

A

two vertical lines, one longer than the other

15
Q

15 How can you tell which is the negative terminal of a cell from the circuit symbol?

A

It is the shorter line.

16
Q

16 What is the difference between conventional current and the flow of electrons?

A

Electrons flow from the negative terminal of a cell to the positive terminal, conventional current flows the other way.

17
Q

17 What unit is current measured in?

A

amps/amperes

18
Q

18 What is another term for potential difference?

A

voltage

19
Q

19 Which component is used to measure electric current?

A

an ammeter

20
Q

20 What are the units for current?

A

amps or amperes

21
Q

21 What two conditions are needed to give a current in a circuit?

A

closed circuit and potential difference

22
Q

22 Is an ammeter connected in parallel or in series with a component?

A

series

23
Q

23 A series circuit has two lamps. When the current through one lamp is 2A, what is the current through the other lamp?

A

2A

24
Q

24 A parallel circuit has two lamps in parallel. When the current through each lamp is 2A, what is the current from the battery?

A

4A

25
Q

25 Which component is used to measure potential difference?

A

a voltmeter

26
Q

26 What are the units for potential difference?

A

volts

27
Q

27 Current can be described as the rate of flow of charge. In a metal, what are the charged particles that flow?

A

electrons

28
Q

28 In a circuit, energy is transferred to a charge. Where is this energy transferred from?

A

cell/battery/power supply

29
Q

29 What is an electric current?

A

a flow of charge

30
Q

30 State the unit and the symbol for current.

A

amp/ampere, A

31
Q

31 State the unit and the symbol for charge.

A

coulomb, C

32
Q

32 Write down the equation relating the total charge that flows to current and time.

A

Q = I x t

33
Q

33 State the unit and the symbol for potential difference.

A

volt, V

34
Q

34 How many volts is one joule per coulomb?

A

1V

35
Q

35 Write down the equation relating the energy transferred in a circuit to the potential difference.

A

E = Q x V

36
Q

36 Describe the potential difference between two points in terms of energy transferred.

A

It is the energy transferred when 1 coulomb of charge moves from one point to the other.

37
Q

37 State the unit for electrical resistance.

A

ohm

38
Q

38 Write down the equation that is used to work out electrical resistance.

A

R = V / I

39
Q

39 What unit is used to measure resistance?

A

ohms

40
Q

40 What is the symbol for a resistor?

A

a rectangle

41
Q

41 What is the symbol for a variable resistor?

A

a rectangle with an arrow through it

42
Q

42 What equation connects potential difference, current and resistance?

A

V = I x R

43
Q

43 A circuit contains a resistor. If another resistor is added in series with the first, does the total resistance in the circuit increase, decrease or stay the same?

A

increase

44
Q

44 A circuit contains a resistor. If another resistor is added in parallel with the first, does the total resistance in the circuit increase, decrease or stay the same?

A

decrease

45
Q

45 When resistors are connected in series, how can you calculate the total resistance?

A

46
Q

46 When the potential difference across a fixed resistor is doubled, what happens to the current?

A

the current doubles

47
Q

47 What happens to the resistance of a light-dependent resistor LDR when light intensity increases?

A

It decreases

48
Q

48 What happens to the resistance of a thermistor when the temperature increases?

A

it decreases

49
Q

49 What is the name of a resistor that can be changed by adjusting a dial?

A

a variable resistor

50
Q

50 Which component could be used to change the current in a circuit when the temperature changes?

A

a thermistor

51
Q

51 Which component could be used to change the current in a circuit when the light intensity changes?

A

a light-dependent resistor

52
Q

52 What does a diode do?

A

conducts electricity in only one direction

53
Q

53 What happens to the resistance of a filament lamp when the potential difference is increased?

A

it increases

54
Q

54 What happens to the resistance of a thermistor when the temperature rises?

A

it decreases

55
Q

55 What happens to the resistance of a light-dependent resistor when the light intensity increases?

A

it decreases

56
Q

56 What does the graph of current against potential difference look like for a fixed resistor?

A

straight line through the origin/directly proportional relationship

57
Q

57 When an electric current passes through a high-resistance wire, what happens to the wire?

A

it becomes hot

58
Q

58 How can resistance in the wires in circuits be reduced?

A

cool the wire / use low-resistance wire / make the wire thicker / make the wires as short as possible

59
Q

59 Give an example of an appliance that uses the heating effect of a current.

A

e.g. kettle

60
Q

60 Give an example of a disadvantage that can result from overheating by an electric current.

A

e.g. fire, damage to the appliance/wires

61
Q

61 If the new connecting wires in a house have a lower resistance than the old ones, what effect will this have on daily electricity use?

A

it will be less

62
Q

62 When electrons move through a lattice of positive ions, what happens to cause electrical resistance?

A

collisions

63
Q

63 When a resistor heats up, what happens to the positive ions to increase resistance?

A

they vibrate more

64
Q

64 What is the equation that connects energy transferred to current, potential difference and time?

A

E = I x V x t, energy transferred = current x potential difference x time

65
Q

65 H Apart from using lower resistance wires and without changing any components, state one way the resistance in a circuit can be reduced.

A

thicker wires, cooling

66
Q

66 H State a second way the resistance in circuits can be reduced.

A

low resistance materials, thicker wires, or cooling

67
Q

67 What is the unit for measuring power?

A

watts

68
Q

68 Power is the transfer of what each second?

A

energy

69
Q

69 Name the unit and give the symbol for power.

A

watt, W

70
Q

70 Which is more powerful: kettle A, which boils a mug of water in 1 minute, or kettle B, which boils a mug of water in 2 minutes, or do they both have the same power?

A

A

71
Q

71 Write down an equation that links power to energy transferred, E.

A

or in words

72
Q

72 Which uses more power: A a 12 V 20 W lamp, or B a 240 V 9 W lamp or do they both use the same power?

A

A

73
Q

73 Write down an equation that links power to current and potential difference.

A

P = I x V or in words

74
Q

75 What is the mains voltage in the UK?

A

230 V

75
Q

76 What is the frequency of the a.c. mains voltage in the UK?

A

50 Hz

76
Q

77 What type of energy store does a battery have?

A

chemical

77
Q

78 At some time after energy is transferred to an electric toothbrush, in what energy store does the energy end up?

A

in the thermal store of the surroundings

78
Q

79 What do the letters d.c. mean?

A

direct current

79
Q

80 Describe the way the electrons move in d.c.

A

in one continuous direction

80
Q

81 What do the letters a.c. mean?

A

alternating current

81
Q

82 Describe the way the electrons move in a.c.

A

keep reversing direction

82
Q

83 What are the names of two of the wires in a plug?

A

two of: live, neutral, earth

83
Q

84 What is the name of one electrical safety feature found in our homes apart from the earth wire of a plug?

A

Circuit breaker or fuse

84
Q

What component of an electrical circuit does this symbol represent?

A

Open switch

85
Q

What component of an electrical circuit does this symbol represent?

A

Closed switch

86
Q

What component of an electrical circuit does this symbol represent?

A

Lamp

87
Q

What component of an electrical circuit does this symbol represent?

A

Voltmeter

88
Q

What component of an electrical circuit does this symbol represent?

A

Ammeter

89
Q

What component of an electrical circuit does this symbol represent?

A

Resistor

90
Q

What component of an electrical circuit does this symbol represent?

A

LDR

91
Q

What component of an electrical circuit does this symbol represent?

A

Thermistor

92
Q

What component of an electrical circuit does this symbol represent?

A

Variable Resistor

93
Q

What component of an electrical circuit does this symbol represent?

A

Diode

94
Q

What component of an electrical circuit does this symbol represent?

A

LED

95
Q

What component of an electrical circuit does this symbol represent?

A

Fuse

96
Q

What component of an electrical circuit does this symbol represent?

A

Cell

97
Q

What component of an electrical circuit does this symbol represent?

A

Battery

98
Q

Is this an example of a series circuit or a parallel circuit?

A

Series

99
Q

Is this an example of a series circuit or a parallel circuit?

A

Parallel

100
Q

True/False: You can run your finger all the way through a series circuit from the battery to all the components

A

True

101
Q

True/False: You can run your finger all the way through a parallel circuit from the battery to all the components

A

False

102
Q

In a series circuit, the voltmeter has to be in series/in parallel around the component

A

in parallel

103
Q

What is charge?

A

The value of electricity flowing through a circuit

104
Q

What is current?

A

The flow of electrons

105
Q

What is potential difference?

A

What pushes the current around

106
Q

What is resistance?

A

Anything that slows down the current

107
Q

Energy =

A

charge x potential difference

108
Q

What is charge measured in?

A

coulombs

109
Q

Charge =

A

Current x time

110
Q

In a series circuit, electrons all move in the same/different paths

A

The same

111
Q

The current in a series circuit changes/stays the same

A

Stays the same

112
Q

Current in a parallel circuit is…

A

split across the branches

113
Q

What is potential difference measured by?

A

A voltmeter

114
Q

In a series circuit, potentiall difference is split/the same across components

A

Split

115
Q

In a parallel circuit, potentiall difference is split/the same across components

A

The same

116
Q

With resistors in series, the total resistance is…

A

117
Q

With resistors in parallel, the total resistance is…

A

1/resistance1 + 1/resistance2 etc

118
Q

Current in a series circuit is…

A

The same wherever you look at it

119
Q

What must you do with different potential differences in a series circuit to get the total potential difference?

A

120
Q

What must you do with different resistances in a series circuit to get the total resistance?

A

121
Q

In a parallel circuit, the current on each branch is equal to…

A

the total current

122
Q

In a parallel circuit, the potential difference in each branch is…

A

The same

123
Q

Potential difference =

A

Current x resistance

124
Q

In a current/potential difference graph, what is the relationship between a resistor and a constant temperature?

A

They are directly proportional

125
Q

What does this current/potential difference graph represent?

A

A filament bulb

126
Q

What does this current/potential difference graph represent?

A

A diode

127
Q

Diodes let current flow in multiple directions/only let current flow in one direction

A

Only let current flow in one direction

128
Q

What is a thermistor used in?

A

Things like central heating

129
Q

Thermistors only let _______ flow at certain temperatures

A

current

130
Q

What does this graph show about the flow of current from thermistors?

A

Only lets current flow at certain temperatures - the graph is more steep at high temperatures. As the temperature changes, the resistance changes

131
Q

What does LDR stand for?

A

Light Dependant Resistor

132
Q

What are LDRs used in?

A

Street lights and security lights

133
Q

What does this graph show about how resistance flowing through a circuit is affected by light?

A

Resistance flowing through the circuit changes with the amount of light

134
Q

Energy =

A

Current x potential difference x time

135
Q

Power =

A

energy transferred

time

or

potential difference x current

or

current2 x resistance

136
Q

What is resistance measured in?

A

Ohms

137
Q

Mains electricity in the UK is ___V and __Hz

A

250V and 50Hz

138
Q

What goes through the fuse?

A

A very small bit of wire

139
Q

What happens to the wire in the fuse if too much current goes through it?

A

It will melt

140
Q

Why does the wire in the fuse melt if too much current goes through?

A

This protects the wiring and the appliance if something goes wrong

141
Q

Name the 3 wires in a plug

A

Live wire, earth wire and neutral wire

142
Q

Which wire, neutral, earth or live is a safety feature of plugs?

A

Earth

143
Q

What holds wires down in a plug?

A

Pins

144
Q

True/False, the cable grip in a wire is a safety feature

A

True

145
Q

What does the cable grip do?

A

Makes sure the wire doesn’t go anywhere

146
Q

The cable for a plug is ______ incased in plastic

A

double

147
Q

Why are plugs cased in plasted?

A

Safety reasons

148
Q

What does AC stand for?

A

Alternating Current

149
Q

What does DC stand for?

A

Direct current

150
Q

Alternating Current comes from…

A

Mains electricity

151
Q

Direct current comes from…

A

Batteries

152
Q

What is alternating current?

A

Current that changes - it goes one way or the other way

153
Q

What is direct current?

A

Current that just goes one way

154
Q

What is static electricity?

A

An object that isn’t normally charged becoming charged

155
Q

What causes static electricity?

A

Two insulators rubbing together

156
Q

What causes two insulators to rub together?

A

The movement of electrons from one thing to another

157
Q

What happens when static electricity charges reset?

A

You get a shock

158
Q

How do static electricity charges reset?

A

When you touch something metal

159
Q

Two charged objects coming together will _____ each other

A

Repel

160
Q

A charged object and an oppositely charged object will _______ each other

A

attract