Electricity Flashcards
(136 cards)
1
Q
Name the component that changes its resistance as the temperature changes.
A
thermistor
2
Q
Name the component used in electric circuits that is sensitive to temperature.
A
thermistor
3
Q
_______ = power / potential difference
A
current
4
Q
current = ______ / potential difference
A
power
5
Q
current = power / __________ __________
A
potential difference
6
Q
_______ = charge / time
A
current
7
Q
current = ______ / time
A
charge
8
Q
current = charge / ____
A
time
9
Q
Electric current is a flow of electric __________.
A
charge
10
Q
What units are used for the rate of flow of electric charge?
A
amps
11
Q
A coulomb is a measure of… what?
A
charge
12
Q
Which special component would you need to use in a thermostat so that it can respond to changes in temperature?
A
thermistor
13
Q
what is the name given to two or more cells in series
A
battery
14
Q
diodes only let current flow in ___ __________
A
one direction
15
Q
_______ only let current flow in one direction
A
diodes
16
Q
diodes only let ________ flow in one direction
A
current
17
Q
An electric current flows when what move through a conductor?
A
charge
18
Q
Name the component used in electric circuits that is sensitive to light
A
light dependent resistor
19
Q
A ____ is made up of a thin wire designed to melt if too much current flows through it.
A
fuse
20
Q
A fuse is made up of a ____ ____ designed to melt if too much current flows through it.
A
thin wire
21
Q
A fuse is made up of a thin wire designed to ____ if too much current flows through it.
A
melt
22
Q
A fuse is made up of a thin wire designed to melt if too much _______ flows through it.
A
current
23
Q
Should an ammeter be connected in series or in parallel?
A
series
24
Q
True or false? A current is present wherever there is a flow of electrical charge.
A
true
25
An LDR can be used in a circuit to provide an input to a logic gate. What does LDR stand for?
Light Dependent Resistor
26
Which special component would you use to detect the light levels in a circuit that switches lights on automatically when it gets dark?
Light Dependent Resistor (LDR)
27
What name is given to the rate of flow of electric charge?
current
28
_______ = potential difference / resistance
current
29
Current = potential difference / _________
resistance
30
Current = ____________ ____________ / resistance
potential difference
31
Voltage is another name for the __________ difference
potential
32
Karl measures the current through a resistor. What else will he need to measure in order to work out its resistance?
potential difference
33
Potential difference = _______ / charge
energy
34
Potential difference = energy / _______
charge
35
__________ __________ = energy / charge
potential difference
36
What name is given to the work done per coulomb of charge passing between two points?
potential difference (voltage)
37
For a given potential difference, a bigger resistance means a smaller __________ through a component.
current
38
True or false? Potential difference is measured in joules.
false
39
what is potential difference measured in?
volts (V)
40
Resistance is equal to the potential difference divided by what?
current
41
What is the relationship between the current through a resistor and the potential difference across it at constant temperature?
directly proportional
42
The resistance of a component can be found by measuring the potential difference across it and the __________ that travelled through it.
current
43
What units are used to measure resistance?
ohms (Ω)
44
A diode has a high resistance in the __________ direction.
reverse
45
At low temperatures, will a thermistor have a high or a low resistance?
high resistance
46
A diode is a device that has an extremely high __________ in one direction and a low __________ in the other.
resistance
47
At high temperatures is the current through a thermistor high or low?
high
48
LDRs are sometimes used in automatic lights that turn on when it gets dark outside. When it gets dark outside, the resistance of the LDR will be __________. What word completes the sentence?
high
49
What happens to the temperature of a filament when an electric current passes through it?
increases
50
Will the resistance of a filament lamp increase, decrease or stay the same if the temperature of its filament decreases?
decrease
51
What happens to the temperature of a resistor when electrical charge flows through it?
increases
52
Name the component that changes its resistance as the light intensity changes
light dependent resistor (LDR)
53
Name the type of component through which current only flows in one direction
diode
54
Use of LEDs for lighting is increasing because they use a much smaller __________ than other types of lighting
current
55
An LED is useful because when a current passes through it, it gives out... what?
light
56
In bright light, will an LDR have a high or a low resistance?
low resistance
57
Which electrical component is used for detecting light levels in digital cameras?
light dependent resistor (LDR)
58
The current-potential difference graph for a resistor is a straight line as long as the __________ is constant
temperature
59
Name the type of component that has a greater resistance as the current through it increases
filament bulb
60
True or false? LEDs will only produce light if the current flows through them in the forward direction
true
61
A diode has a very high __________ in one direction
resistance
62
There is an increasing use of LEDs for lighting. What does LED stand for?
light emitting diode
63
True or false? The current through a filament lamp is directly proportional to the potential difference across it.
false
64
In the dark, is the current through an LDR higher or lower than in the light?
low
65
Three 1.5V cells are connected in series in a circuit. What will happen to the current flowing through this circuit if one of the cells is removed?
decrease
66
True or false? If two components are connected in series, the current through one component will always be the same as the current through the other.
true
67
Three 1.5V cells are connected in series in a circuit. What is the total potential difference?
4.5V (1.5V + 1.5V + 1.5V)
68
In a series circuit, the current is __________ at every point around the circuit
equal
69
True or false? The potential difference across two components connected in series will always be the same
false
70
True or false? The sum of the potential differences across the components in a series circuit is equal to the total potential difference across the supply
true
71
Potential difference in a parallel circuit is the ____ across each branch
same
72
Potential difference in a ________ circuit is the same across each branch
parallel
73
___________ ___________ in a parallel circuit is the same across each branch
potential difference
74
Which piece of equipment would you use to measure the current in a circuit?
ammeter
75
In a circuit with two identical components connected in parallel, the current which flows through its different branches will be __________
the same
76
True or false? The current through two components connected in parallel will always be equal
false
77
You connect an ammeter to a circuit. The ammeter shows you that there are 5 amperes of __________ in the circuit.
current
78
What colour is the neutral wire in a UK electric cable?
blue
79
The Earth wire provides a ___________ to the ground to help prevent you from getting an electrical shock
connection
80
The Earth wire provides a connection to the _______ to help prevent you from getting an electrical shock
ground
81
The Earth wire provides a connection to the ground to help prevent you from getting an _________ ______
electrical shock
82
The ________ wire is the earth wire
striped
83
The striped wire is the ______ ____
earth wire
84
earth wire is only used when __________ _____ _______
something goes wrong
85
_____ _____ is only used when something goes wrong
earth wire
86
UK Mains voltage is ____
230V
87
__ _______ voltage is 230V
UK Mains
88
UK Mains ________ is 230V
voltage
89
potential difference between the brown wire and striped wire is ____
230V
90
What colour is the live wire in a UK electric cable?
brown
91
True or false? The period of an AC supply is equal to the time between an adjacent peak and trough on an oscilloscope trace.
false
92
What is the voltage of the blue wire
0V (because it’s neutral)
93
Should a two-core cable or a three-core cable be used for an electrical appliance made from metal?
three-core cable
94
What is the frequency in hertz of the UK mains electricity supply?
50Hz
95
What is the main electricity supply in the UK?
alternating current
96
Below is an oscilloscope trace. What type of current produced it?
alternating current (AC)
97
True or false? The period of an AC supply is the time taken for one complete oscillation
true
98
An alternating current is one that is constantly changing __________
direction
99
True or false? Cells and batteries supply current that always passes in the same direction
true
100
A kettle is made from metal. If the live wire inside this kettle were to come loose and touch the metal casing, you could get an __________ __________ if you then touched the kettle
electric shock
101
What type of current is supplied by cells and batteries?
direct current
102
A high current in a faulty appliance will flow to earth through the earth wire because this wire has a very low... what?
resistance
103
Electricity is sent through power lines at very high voltages in order to limit energy losses. True or false?
true
104
______ = current2 × resistance
power
105
Power = current2 × ___________
resistance
106
Power = ___________ × resistance
current^2
107
The ____________ ______ transfer electricity between power stations and consumers
transmission lines
108
The transmission lines transfer ___________ between power stations and consumers.
electricity
109
The transmission lines transfer electricity between ______ _________ and consumers
power stations
110
When using the equation for power (P = E / t) what is time measured in?
seconds
111
Cables that are used to transfer energy electrically will heat up. One disadvantage of this is something is lost from the cables in the form of heat. What is lost?
thermal energy
112
For a given power, will increasing the voltage increase or decrease the current?
decrease
113
The ________ is highest in the transmission lines, so that they can have a low current to reduce energy loss
voltage
114
The voltage is highest in the ______________ _____ , so that they can have a low current to reduce energy loss
transmission lines
115
The voltage is highest in the transmission lines, so that they can have a ___ _______ to reduce energy loss.
low current
116
The voltage is highest in the transmission lines, so that they can have a low current to _______ ________ ____
reduce energy loss
117
An electric drill has energy in its __________ energy store when it is rotating.
kinetic
118
The power of an electrical appliance is a measure of how quickly it transfers... what?
energy
119
Does a step-down transformer increase or decrease the voltage?
decrease
120
Energy transferred electrically is measured in __________. What one word completes the sentence?
joules
121
The consumer is who uses the electricity (_______)
houses
122
The ___________ is who uses the electricity (houses)
consumer
123
The consumer is who uses the __________ (houses)
electricity
124
What is this formula used to calculate? I² × R
power
125
True or false? A high current should be used when transmitting electricity so that less power will be lost
false
126
If you want to find the amount of energy electrically transferred, multiply the charge by the... what?
potential difference
127
You can find the power of an electrical appliance by measuring the energy it transfers in a certain... what?
time
128
What name is given to the system that distributes electricity from power stations around the UK?
national grid
129
Power lines are dangerous because they carry electricity with a very high current. True or false?
false
130
For an amount of electrical charge that moves, the amount of energy transferred increases as the potential difference... what?
increases
131
Is more or less heat produced if the current carried by a wire is increased?
more
132
The main disadvantage of the high voltage used to distribute electricity around the UK is that it is... what?
dangerous
133
Electricity can be distributed around the UK using overhead power lines or underground cables. Besides their being difficult to access, the main disadvantage of underground cables is that they are more __________
expensive
134
Does a step-up transformer increase or decrease voltage?
increase
135
Name the component used in electric circuits that is sensitive to light.
LDR
136
What are the main disadvantages of underground cables?
- difficult to access
- expensive
