Electricity Flashcards
1
Q
What is the energy change in a lamp?
A
Electrical to light (+ heat)
2
Q
Name one source of AC
A
Mains supply
3
Q
What is the rule for current in a series circuit?
A
The current is the same everywhere
4
Q
What is the energy change in a buzzer?
A
Electrical to sound
5
Q
What is current?
A
The charge transferred per second
6
Q
What is the energy change in an LED?
A
Electrical to light
7
Q
Which device measures voltage?
A
Voltmeter
8
Q
What happens if you increase the resistance in a circuit?
A
The current will decrease
9
Q
Which circuit component is represented by the following diagram?
A
Loudspeaker
10
Q
What is DC?
A
Direct current. Electrons move in one direction only.
11
Q
Which component does the symbol represent?
A
Buzzer
12
Q
How can you identify a series circuit?
A
It is a circuit with only one path round it.
13
Q
Name one source of DC
A
Battery
14
Q
Which device measures resistance?
A
Ohmmeter
15
Q
Which circuit component is represented by the following diagram?
A
Light Emitting Diode
16
Q
What is the rule for voltages in a parallel circuit?
A
The voltage across each branch is equal to the supply voltage.
17
Q
Which circuit component is represented by the following diagram?
A
Battery
18
Q
Which circuit component is represented by the following diagram?
A
Lamp
19
Q
What is AC?
A
Alternating current. The electrons change direction, moving backwards and forwards, many times in a second.
20
Q
How can a parallel circuit be identified?
A
It is a circuit with more than one path round it.
21
Q
What is the symbol for a voltmeter?
A
Circle with a V in it
22
Q
How can power losses be reduced in transmission lines?
A
By increasing the transmission voltage and so decreasing the transmission current.
23
Q
Which circuit component is represented by the following diagram?
A
Motor
24
Q
Which device measures current?
A
Ammeter
25
How can you tell from this oscilloscope image that this is AC?
The trace shows a change in direction
26
How should an ammeter be connected to measure the current in a component?
It should be connected in series with the component
27
What happens if you unscrew one of the lamps in the circuit below? Why?
The other lamps go out. There is a break in the circuit and the current does not have a complete route to the battery.
28
What is the energy change in a motor?
Electrical to kinetic
29
What is the rule for voltages in a series circuit?
The voltage across each component added together is equal to the supply voltage.
30
What is the energy change in a buzzer?
Electrical to sound
31
Which circuit component is represented by the following diagram?
Resistor
32
What type of current is represented by this oscilloscope image?
DC
33
Which circuit component is represented by the following diagram?
Switch
34
What type of current is represented by this oscilloscope image?
AC
35
What is the symbol for an Ohmmeter?
Circle with an Omega in it
36
Which circuit component is represented by the following diagram?
Cell
37
What is the symbol for an ammeter?
Circle with an A in it.
38
What is the energy change in a photovoltaic cell?
Light to electrical
39
What is the rule for current in a parallel circuit?
The supply current is equal to the current in each branch added together.
40
What is the energy chage in a battery?
Chemical to electrical
41
What is the stated value of the mains?
230V, 50Hz
42
How should a voltmeter be connected to measure the voltage across a component?
It should be connected across the component
43
What is the energy change in a battery?
Chemical to electrical
44
Describe how to make a battery.
You need two different types of metals and a liquid that can conduct. The metals should not touch and both should be in the liquid.
45
What is an electrode in a battery?
One of the two types of metal.
46
What is an electrolyte in a battery?
The conducting liquid.
47
State 3 factors that can effect the voltage produced by a battery that you might make.
* Types of metals used
* Area of metals used
* Concentration if the electrolyte
* Distance between the electrodes
48
State the definition for voltage.
Number of Joules of energy transferred per coulomb of charge.
49
What is Ohms Law?
V =IR
50
In the equation V=IR, what does V stand for?
Voltage
51
In the equation V=IR, what does I stand for?
Current
52
In the equation V=IR, what does R stand for?
Resistance
53
What is the unit for current?
Amperes or Amps or A
54
What is the unit for Voltage?
Volts or V
55
What is the unit for resistance?
Ohms or Ω
56
Which equation can be used to calculate power?
P = IV
57
In the equation P = IV, what does P stand for?
Power
58
In the equation P = IV, what does the I stand for?
Current
59
In the quation P =IV, what does V stand for?
Voltage
60
What is the unit for current?
Amperes or Amps or A
61
What is the unit for Voltage?
Volts or V
62
What is the unit for Power?
Watts or W
63
What 3 things are required to induce a voltage?
1. Conductor
2. Movement
3. Magnetic field
64
Explain how to induce a voltage.
Move a coil of wire in a magnetic field,
65
State 2 ways that an induced voltage can be increased.
* Stronger magnetic field
* Faster movement
* More coils of wire
66
Why is an induced voltage a.c?
There is a changing direction
67
Explain how a voltage is induced in a dynamo.
A magnet spins inside a coil of wire.
68
What type of magnets are used in a generator?
Electromagnets
69
70
State two methods of generating electrical energy
* Solar cells
* Wind turbines
* Nuclear power station
* Hydro electric
* Coal/oil/gas fired power station
71
State an advantage of generating electrical energy by using wind turbines.
* Does not produce greenhouse gases
* Renewable so it will not run out
72
State a disadvantage of generating electrical energy by using wind turbines.
* It may not always be windy enough to generate enough electrical energy
* People object to them as they spoil the landscape
73
State an advantage of generating electrical energy by using solar cells.
* Does not produce greenhouse gases
* Renewable so it will not run out
74
State a disadvantage of generating electrical energy by using solar cells.
* May not have enough daylight to generate enough electrical energy
* Can be expensive to install
75
State an advantage of generating electrical energy by using nuclear power.
* Does not produce any greenhouse gases
* Produces a large amount of energy per kg of fuel
* Fuel cells can be reprocessed an used again
76
State a disdvantage of generating electrical energy by using nuclear power.
* Produces radioactive waste
* The waste must be stored for hundreds of years
* Expensive to build and decomission
* If there is an accident radioactive material can be released into the environment
77
What is the purpose of a transformer?
To increase or decrease a voltage
78
What does a step up transformer do?
Increases the voltage
79
What does a step down transormer do?
Decreases the voltage
80
Why are transformers used in electrical transmission lines?
To step up the voltage. This decreases the current and reduces the power lost in the transmission lines. At the other end a step down transformer reduces the voltage ready for use in the home.
81
What are the main parts of a transformer?
Primary Coil, Secondary Coil, Iron core
82
What is the energy change in a turbine?
Heat to Kinetic
83
What is the energy change in a generator?
Kinetic to electrical
84
What are solar cells made from?
Semiconductor materials
85
What is the energy change in a solar cell?
Light to electrical
86
State two factors that can change the output of a solar cell.
* Area of solar cell
* Angle of solar cell
* Colour of the light
* Brigtness of light
* Distance fromlight source
87
What is the energy change in a wind turbine?
Kinetic to electrical
88
State two factors that can change the output of a wind turbine.
* Number of blades
* Speed of wind
* Mass of blades
* Angle of blades
89
What is meant by nuclear fission?
When a large mass nucleus splits into smaller mass nuclei releasing energy and neutrons.
90
What is the energy change in a nuclear reactor?
Nuclear to Heat
91
What is the purpose of the shielding in a nuclear reactor?
To prevent any radioactive material escaping from teh reactor.
92
What is the purpose of the control rods?
They absorb neutrons to control the fission reaction.
93
There have been 2 nuclear disasters
1. Fukishima
2. Chernobyl
For **one** of these explain what happened.
Fukishima
Following a major earthquake, a 15-metre tsunami disabled the power supply and cooling of three Fukushima Daiichi reactors, causing a nuclear accident All three cores largely melted in the first three days.
Chernobyl
A nclear reactor exploded during a test to check how the cooling system operated on limited power.The power-regulating and safety systems were both shut off before the test to avoid interruptions.The reactor was to supposed to run at 25 percent capacity during the test but dipped to less than one percent, forcing workers to slowly increase the power levels.
Basically - poor reactor design and staff not trained enough.
