Physics Flashcards
1
Q
Who came up with the heliocentric model
A
Nicolaus Copernicus
2
Q
Who proved the heliocentric model and pioneered observations with telescopes
A
Galileo Galilei
3
Q
How have we started discovering new planets
A
As telescopes improve scientists have discovered new planets
Copernicus’s model of the universe didn’t include Uranus Neptune or the dwarf planet Pluto because telescopes at the time weren’t good enough to see them
4
Q
Who was Galileo and what did he do
A
Was an Italian astronomer who worked at a time when all scientists believed the earth was the centre of the universe, using the telescope he discovered Jupiter had four moons
This showed that not everything orbited the earth proving Copernicuss theory correct
This put him into conflict with the church as they believed the geocentric model
He spent a large amount of his life in house arrest as a result
5
Q
How do we know stuff about stars
A
Analysing the radiation they produce
6
Q
Ground operated optical telescopes disadvantages
A
They can only be used at night
They cannot be used if the weather is poor or cloudy
7
Q
telescopes used on earth
A
Optical telescopes
They can only be used at night
They can not be used if the weather is poor or cloudy
Radio telescopes Detect radio waves from space Very large and expensive Can be used in bad weather because radio waves are not blocked by clouds Can be used at day and night
X-ray telescopes
Partially blocked by our atmosphere so have to be at high altitudes or flown in balloons
8
Q
Space telescopes (3)
A
Infrared, X-rays, gamma rays
9
Q
Positives and negatives about space telescopes
A
Negatives:
They are difficult and expensive to launch and maintain
If anything goes wrong only astronauts can fix them
Positives:
Can operate at both night and day
Can observe the whole night sky
Can monitor other types of radiation like infrared x/rays and gamma rays which are blocked by the earths atmosphere
10
Q
What is a converging/convex lens
A
A lens which is curved outwards on both sides
This makes light rays come to a point- they converge
11
Q
What is the focal point
A
The point at which the light rays meet
12
Q
How do you find the focal length and what is it
A
The focal length is the distance between the centre of the lens and the image
You find the focal length by focusing a distant object on a piece of paper through a lens, keeping the distance of the piece of paper and the lens the same one measures the distance between the two, this is the focal length
13
Q
What would one use a converging lens for
A
A refracting telescope like galileos
14
Q
The amount of magnification a refracting telescope using converging lenses has depends on:
A
How curved the surface of the lens is
How close the lenses are placed
15
Q
What is a real image
A
A real image is the image produced where the light rays are focused
16
Q
What is a virtual image
A
A virtual image is the image from which the light rays appear to come from but don’t actually come from that image, like a mirror
17
Q
How can converging images be investigated
A
Converging lenses can be investigated by measuring the distance from the lens to the object in focal lengths
The image can also be measured in focal lengths
18
Q
Problems with refracting telescopes
A
Some of the light reflects reflects off the lens so the image is very faint
Large lenses are required to improve the magnification this can be difficult to do perfectly
19
Q
How does a reflecting telescope produce a magnified image
A
The image is formed by reflecting off a curved mirror
It is then magnified by a second mirror
20
Q
What are waves
A
Waves are vibrations that transfer energy without matter being transferred
21
Q
What is the substance waves move through known as
A
The medium
22
Q
What are longitudinal waves
A
The vibrations are along the same direction as the direction of travel
23
Q
What sort of wave is a p wave and what is it
A
Longitudinal waves produced by earth quakes
24
Q
What are transverse waves
A
The vibrations of the wave are at right angles to the direction of travel
25
Give 3 examples of a transverse wave
```
Light (includes other types of radiation)
Water waves
S waves ( a type of seismic wave)
```
26
What is the amplitude of a wave
The amplitude of a wave is its maximum disturbance from an undisturbed position
27
What is the wavelength of a wave
The wavelength is the measurement between one point on the wave and the same point on the next wave this is usually the crest
28
What is wave frequency
The number of waves going past a point or produced at the source every second
29
What is the unit of frequency
Hertz (hz)
30
What is the relationship between the angle of incident and the angle of reflection
The angle of incident and the angle of reflection are the same
31
What is the wave that is not reflected called
The incident ray
32
What is the ray that bounces off the surface called
The reflective ray
33
How do rough surfaces react when light hits them
They scatter the light but they still follow the rule that the angle of incident is equal to the angle of
reflection on each tiny bit
34
What is refraction
Sound and light waves change speed when they enter a material with a differ ant density this causes a change in direction called refraction
35
What happens if an incident ray went into a material of different density at 90 degrees
The wave slows and it's wavelength decreases as it enters the material
As the wave exits the change in density the wave speed and wavelength return to normal
36
Who created the geo centric model
Ptolemy
37
How do you form a light spectrum
Using a prism
The light waves are refracted as they enter and leave the prism
The shorter the wavelength of the light the more it is refracted
As a result red light is refracted the least and violet light is refracted the most causing the couler ex light to spread out
38
Do all the electromagnetic waves travel at the same speed through space
Yes
39
Who discovered infrared
William Herschel
40
How did William Herschel discover infrared light
He put differsnr coloured filters over his telescope in order to make his observations safer
He noticed differsnr coloured filters produced differsnr amounts of heat
He used a prism do break up the light spectrum and put a thermometer on each colour
He found that the temperature rose as he moved from violet to red
He then measured the temperature of the spectrum where there was no visible light on the red side
The temperature was the highest
41
Who discovered ultraviolet light
Johann Ritter
42
How did johann Ritter discover ultraviolet
Following hershals work Ritter tried to find invisible rays on the violet end of the spectrum
He used silver chloride which turns black when exposed to light
This happened he fastest when exposed to the invisible rays on the violet end of the spectrum
43
All types of electromagnetic radiation:
Are transverse waves
Travel at the same speed in a vacuum
44
What are the main types of electromagnetic rays in order of frequency and wavelength
```
Highest at the top:
Gamma radiation
X-rays
Ultraviolet
Visible light
Infrared
Microwaves
Radio waves
```
45
What is the speed of light in a vacuum
Approx three hundred million metres per second
46
What is the danger of microwaves
Internal heating to the body
47
What is the danger of infrared
External heat
| Causes skin burns
48
What is the danger of X-rays
Is ionising so causes DNA mutations so sometimes cancer
Cell death
Cell damage
49
Dangers of gamma rays
Damage cells
Cause mutations because they are ionising
Cell death
50
Uses of microwaves
Transmit signals like for mobile phones
Transmitters and rescue vets communicate with phones within their range
There is concern that microwaves from phones and masts may damage our health
51
How do our skins respond to uv light
We can not see or feel it but our skin responds to it by turning darker
Darker skin absorbs more ultraviolet light so less of it penetrates our skin to reach deeper tissues
This is good because iv has been shown to cause cancer
52
What are the three types of uv
Uv : c b and a
53
What are the frequencies of the different types of uv and what are the side effects
Uv c: has a high frequency
Causes severe damage to cells
Uv b: causes severe sunburn and cell damage
Uv a: causes weaker effects to uv b
54
Two uses of radio waves
Broadcasting information
Satellite transmissions
55
Three uses of microwaves
Cooking
Communications
Satellite transmissions
56
Six uses of infrared
```
Cooking
Security systems
TV remote controls
Optical fibres
Short range communications
Thermal imaging
```
57
Three uses of visible light
Vision
Photography
Illumination
58
4 uses of uv
Security marking
Disinfecting water
Fluorescent lamps
Detecting forged bank notes
59
Two uses of gamma rays
Sterilising food and medical equipment
Detecting of cancer and the treatment of it
60
In an exam question asking about uses of electromagnetic radiation you should
Advantages and disadvantages of each type of electromagnetic radiation
Indicate the precise use and why
Include information about frequency and wavelength
61
What are the three types of ionising nuclear radiation
Alpha
Beta
Gamma
62
What does ionising radiation do
It knocks electrons out of atoms to form charged particles
63
4 uses of the three types of radiation
Detect smoke
Gauge the thickness of paper
Treat cancer
Sterilise medical equipment
64
What are substances that give out radiation said to be
Radioactive
65
Where does nuclear radiation come from
The nucleus of an atom
66
Which type of radiation is the most penetrating
Gamma
It can travel long distances low levels can penetrate paper thin metal and air
High levels can only be stopped by many centimetres of lead or many metres of concrete
67
Which type of radiation is the least penetrating
Alpha
| It can be stopped by a piece of paper
68
How penetrative is beta radiation
Can penetrate air and paper
| It can be stopped by a thin sheet of aluminium
69
How many galaxies is the universe thought to have
Over 1 billion
70
What does a solar system consist of
A star
Planets and dwarf planets in orbit around the star
Satellites (moons) in orbit around the planets
Comets and asteroids in orbit around the sun
71
How many planets and dwarf planets are thee around the solar system
8
72
What is a single orbit around the sun called for a planet
A year
73
What is the shape of an orbit of a comet
An ellipses
74
What is the shape of an orbit of a planet
Very circular
75
How do astronomers help work out the sizes of planets
They use telescopes
| Through this they can also work out the distances between them
76
How many times larger is the distance between one star to another in the galaxy compared to one planet to another
Millions of times more
77
Distance from earth to the sun
150,000,000 km
78
Three examples of space probes and what they did
Viking 1 and Viking 2
Landed on Mars in the 70s took photographs and analysed soil samples
Mars global surveyor
Went into orbit around mars in 1997 and mapped the surface in 3d
Spirit and oportunity:
Two robot vehicles that landed on Mars in 2004
79
Give an example of a space telescope
The Hubble space telescope
80
What is SETI
The search for extra terrestrial intelligence programme
It uses radio telescopes for un natural signals coming from space
81
What do space probes do
Space probes photograph planets in search of life
We have photos of channels on mars that May have been crated by flowing water
Landers touch down on planets and take a soil sample which is used to analyse for evidence of life
82
What is a spectrometer
Light can be split into its spectrum of colours using a spectrometer
Different light sources will give Different
Colours through the spectrometer different versions of the colours are called different spectra
For example sunlight will have black lines in the spectra as the atmosphere absorbs some of the suns light
83
What are the planets in order
```
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
```
84
How long ago do scientists think the Big Bang happened
13,700 million years ago
85
What is it called if the universe was to contract
The Big Crunch
86
What does the oscillating theory suggest
That this universe is one of many
Some that have existed in the past some that will exist in the future
When the universe contracts in the Big Crunch the theory states that a new universe is created in a new Big Bang
87
What does the steady state theory state
The theory suggests that as the universe expand new matter is created so that the overall appearance of the universe never changes
88
The birth of a star three steps
Stars form from massive clouds of dust and gas in space
Gravity pulls the dust and gas together
As the gas pulls together it gets hot a star forms when it gets hot enough for nuclear reactions to start.
The outward pressure from the expanding hot gases is balanced with the gravity of the star out sun is at this stable phase of life
Gravity pulls smaller clouds of gas and dust together which forms planets in orbit around the star
89
What type of star is the sun
Yellow dwarf
90
What happens to stars once they start running out of hydrogen as fuel
Gravity makes the core of the star smaller and hotter which results in the outer layers expanding they eventually expand so much that the star turns into a red giant
91
What happens after the red giant star phase if it's mass is relatively small
If it's mass is relatively small gravity eventually leads to the star contracting to form a red dwarf it fades and changes colour as it cools the matter of a white dwarf is a million times denser than the matter on earth
92
The two pieces of evidence for the Big Bang theory
Red shift
Cosmic microwave background (Cmb) radiation
93
What is the change in wave frequency relative to an observer due to a moving source called
The Doppler effect
94
How can we know that the sun contains helium
There are black lines in the spectrum of light where helium has absorbed light
95
How do we know red shift is happening
The black lines where helium has absorbed light exist on different parts of the light spectrum in other stars compared to the suns ( specifically towards the red end) this shift is a form of the Doppler effect and it's called red shift
The change in frequency shows us that distant galaxies are moving away from us the further away the galaxy the faster it is moving
This is evidence suggests that matter is moving away from itself which is evidence for an expanding universe
The Big Bang theory states that this started billions of years agog with an explosion
96
What is cosmic background radiation
Microwaves coming from every direction from space
Big Bang theory states that this is energy produced in the beginning of the universe just after the Big Bang and that has been travelling through space ever since
97
What caused the Big Bang theory to be the accepted theory
Red shift is used to explain both steady state and the Big Bang theory but cosmic microwave background radiation only is evidence for the Big Bang theory
98
What happens to a heavy weight star after the red giant phase
It blows apart in a massive explosion called a supernova
Then there is only the central part left behind which forms a neutron star or a black hole if it is heavy enough
Black holes have a large mass and a large gravity even light can't escape them
99
What is a nebula
A cloud of dust and gas from which a star forms
100
What does a massive star form when it has used its hydrogen and helium
A red super giant
101
What is the reaction in stars
Nuclear fusion between hydrogen to form helium
102
What happens to a small red giant
It contracts to form a white dwarf
103
What happens to a large medium or super red giant
It goes on making nuclear reactions until a large explosion called a supernova happens leaving a neutron star
104
What happens to a really dense neutron star
Collapses to form a black hole
105
How old is the sun
5 billion years
106
Why does the sun seem bigger than other stars
Because it's closer to earth
107
How far away from centre of the galaxy is the sun
Half way
108
How far away are we from the next galaxy
2.5 million light years
109
How many other galaxies are there
One hundred thousand million
110
Most asteroids are found between which planets
Mars and Jupiter in the asteroid belt
111
What is the definition of ultrasound
Sounds with frequencies above 20,000hz
112
What is the normal range of human hearing
20hz-20khz
113
How is ultrasound used for imaging
Computers are able to produce images by combining many ultrasound reflection readings. This is used in medicine for pre-natal scanning (checking unborn babies)
114
How is ultrasound used
| Three ways
Ultrasound for pre natal scanning
Computers are able to produce detailed images by combining many reflection readings
Quality control procedures to check manufactured objects such as railway tracks and oil pipelines for damage of defects. This works by sending ultrasound into the object and if there are any cracks the ultrasound will bounce off and be caught by a detector
Sonar
An ultrasound signal is sent off it bounces off the seabed or a shoal of fish and the echo is detected
The time the wave takes to travel indicates the depth of the sea bed or shoal of fish
115
What is infra sound
Sound below 20hz
116
How is infra sound detected
Using a microphone
117
Four uses of infrasound
Elephants and giraffes use infrasound to communicate
Scientists can track the herds using microphones even if they are hidden in dense forests this helps the conservation and protection of these animals
It can be used to detect volcanic eruptions
As a volcanoes erupts it produces infra sound which can be detected even if the volcanoes is in a remote location a long way away
Scientists can also use infrasound to track the passage of meteors through the atmosphere if a meteor did not burn up and hit a populated area it could cause considerable damage
118
What are the layers of the earth from the outside in and their properties
Crust. relatively thin and rocky
Mantle. Has the properties of a solid but can flow very slowly
Outer core. Made from liquid nickel and iron
Inner cor. Made from solid nickel and iron
119
Why do plates move on the earth
Convection currents in the mantle driven by radioactive decay of elements and heat left from the earths formation
120
What are seismic waves
Shock waves produced by earthquakes
121
How do we detect seismic waves
Seismographs
122
P waves
Type of wave.
Relative speed compared to s waves.
Can travel through.
Longitudinal
Faster
Solids and liquids
123
S waves
Type of wave.
Relative speed.
Can travel through.
Transverse
Slower
Solids only
124
Why do seismic waves change direction
They can be reflected and refracted at boundaries between the crust mantle and core
125
What is the piece of equipment used to detect seismic waves
Seismometer
126
How do scientists work out the epicentre of an earth quake
By using three seismometers. They do this by working out where all three distances meet. This whole process is called triangulation
127
How do S waves travel through the earth
They move slowly and travel through solids only so they are blocked by the liquid core of the earth
128
How do p waves travel through the earth
Longitudinal fast moving. Travel through solids and liquids only
P waves travel through the different states at differ ant speeds so they are refracted at the core when they make a change from solid to liquid
129
Which two things produce doc electricity
Batteries
Solar cells
130
What is the image one should see on an oscilloscope for dc current
A straight line above 0
131
What is the uk mains supply's voltage and frequency
230 volts
And 50hz
It has a frequency because it is ac so the current changes direction
The frequency shows how many times
A second the current changes direction
132
What does the oscilloscope reading show for an ac current
Wavy lines like in a wave diagram
133
What is the process of making an electrical current
Induction
We say the current has been induced
134
How to increase and induced current
Move the magnet faster
Use a stronger magnet
Increase the number of turns on the coil
Increase the area of the coil
135
How do large generators produce electricity instead of moving a magnet in and out of wire and why
They spin a coil in a magnetic field or spin the magnet because it is more efficient
136
Give an example of a small electrical generator
A bicycle dynamo
137
What is a generator
A device that turns kinetic energy into electrical energy
138
Generators that are turned directly
Three
Wind turbines
Hydroelectric turbines
Wave and tidal turbines
139
Steps from which electricity is generated by fossil fuels
Four
1 heat is released from the fuel and boils water to make steam
2the steam turns the turbine
3the turbine turns a generator and electricity is produced
4the electricity goes through transformers to produce the correct voltage
140
2 steps in which directly turning generators produce electricity
The turbine is turned a generator
Electricity is produced
141
The movement of energy energy through a fossil fuel burning or nuclear power station
The energy produced by burning fossil fuels is stored in water as steam
The energy in steam is transferred to movement in a turbine
The movement in the turbine is then transferred to electrical energy
142
Where is useful energy lost in a power station
Three
Heat losses to environment largest portion
Used in the power station
Lost in transmission
143
Benefits of renewable energy
Three
Their supply is not limited
No fuel costs
They generate far less pollution than fossil fuels
144
Give five renewable energy resources
Biomass energy. The energy released from wood for example
Solar energy
Water energy. For example wave machines tidal barrages and hydroelectric power
Geothermal
Wind energy
145
Negatives of wind energy
Noisy
Spoil view for people
Electricity generated depends on the strength of wind
No wind no electricity
146
Give 4 non renewable energy sources
Fossil fuels. Coal oil natural gas
Nuclear fuels. Uranium
147
Which fossil fuel produces the most carbon dioxide
Coal
148
Define the greenhouse effect
The absorption of heat by gases in the atmosphere especially carbon dioxide and methane
149
Which fossil fuel generates the least carbon dioxide
Natural gas
150
What are three negatives to nuclear power
Power stations are expensive to build
Expensive to dismantle old power stations or store radioactive waste
Nuclear waste is a health hazard
151
What is a disadvantage of using a dynamo on a bike
When the bike stops the light goes out
152
How much energy is transferred as useful energy to the customer by fossil fuel power stations
About a third
153
What does a transformer do
Changes the voltage of an ac current
154
What is a transformer that increases the current called
A step uv transformer
155
What is a transformer that decreases the power called
A step down transformer
156
Where are step down transformers used
Mains adapters and rechargers for phones and iPods
157
How does the national grid reduce its energy loss as heat through wires
They increase the voltage which reduces the rate of flow ( current) this works because the higher the current the more energy is lost as heat
158
What is the 25,000 volts produced at power stations transformed to
Three
400,000v 275,000v 132,000v
159
Why are voltages reduced at towns and villages.
Step down transformers are used to reduce voltages because high voltages are dangerous for people living in settlements
160
Why are power lines and sub stations dangerous
An electric shock could potentially kill someone who gets too close to the line
161
What is the relationship between the turns on the coils and the voltage
Primary voltage/secondary voltage = turns on primary coil/ turns on secondary coil
So
Vp/vs=np/ns
162
How many turns do step up transformers have on their primary coil compared to their secondary coil
Have more turns on their secondary coil than on their primary coil
163
How many turns do step down transformers have on their primary coil compared to their secondary coil
Have fewer turns on their secondary coil than on their primary
164
At which voltage is energy supplied to to the home
230 v
165
What is current measured in
Amperes
Amps
A
166
How does one measure amps
An ammeter
167
How must an ammeter be connected in a circuit
In series with components
168
What is the unit for potential difference
Volts
| V
169
How do you use a voltmeter in a circuit
| How to place it
In parallel with the component
170
With which equation can you work out electrical power
Power (watt,w)= voltage (volts,v)Xcurrent(ampere,a)
171
What is power
A measure of how quickly energy is transferred
172
What is the unit of power
The watt
173
What is the equation for power ( not electrical)
Power equals energy divided by time
174
What's the equation for the cost of electricity
Cost=power x time x cost of 1 kWh
175
How do you work out pay back time
Payback time= cost of energy saving measure/money saved each year
176
Disadvantages to buying an energy saving device
Three
Initial cost
Use of extra resources to manufacture the new device
Cost of des postal of old device
177
Two advantages of buying an energy saving device
Cost efficiency
Saving energy and resources
178
To remember all the types of energy remember this synonym
```
Most magnetic
Kids kinetic
Hate heat or thermal
Learning light
Gcse gravitational potential. Chemical. Sound. Electrical.
Energyelastic potential
Names nuclear
```
179
What is efficiency
The fraction of energy supplied to a device that is transferred to a useful form
180
What is the equation for efficiency
(Useful energy transferred/energy supplied) x 100
181
How many forms of energy are there
9
182
Which two things produce doc electricity
Batteries
Solar cells
183
What is the image one should see on an oscilloscope for dc current
A straight line above 0
184
What is the uk mains supply's voltage and frequency
230 volts
And 50hz
It has a frequency because it is ac so the current changes direction
The frequency shows how many times
A second the current changes direction
185
What does the oscilloscope reading show for an ac current
Wavy lines like in a wave diagram
186
What is the process of making an electrical current
Induction
We say the current has been induced
187
How to increase and induced current
Move the magnet faster
Use a stronger magnet
Increase the number of turns on the coil
Increase the area of the coil
188
How do large generators produce electricity instead of moving a magnet in and out of wire and why
They spin a coil in a magnetic field or spin the magnet because it is more efficient
189
Give an example of a small electrical generator
A bicycle dynamo
190
What is a generator
A device that turns kinetic energy into electrical energy
191
Generators that are turned directly
Three
Wind turbines
Hydroelectric turbines
Wave and tidal turbines
192
Steps from which electricity is generated by fossil fuels
Four
1 heat is released from the fuel and boils water to make steam
2the steam turns the turbine
3the turbine turns a generator and electricity is produced
4the electricity goes through transformers to produce the correct voltage
193
2 steps in which directly turning generators produce electricity
The turbine is turned a generator
Electricity is produced
194
The movement of energy energy through a fossil fuel burning or nuclear power station
The energy produced by burning fossil fuels is stored in water as steam
The energy in steam is transferred to movement in a turbine
The movement in the turbine is then transferred to electrical energy
195
Where is useful energy lost in a power station
Three
Heat losses to environment largest portion
Used in the power station
Lost in transmission
196
Benefits of renewable energy
Three
Their supply is not limited
No fuel costs
They generate far less pollution than fossil fuels
197
Give five renewable energy resources
Biomass energy. The energy released from wood for example
Solar energy
Water energy. For example wave machines tidal barrages and hydroelectric power
Geothermal
Wind energy
198
Negatives of wind energy
Noisy
Spoil view for people
Electricity generated depends on the strength of wind
No wind no electricity
199
Give 4 non renewable energy sources
Fossil fuels. Coal oil natural gas
Nuclear fuels. Uranium
200
Which fossil fuel produces the most carbon dioxide
Coal
201
Define the greenhouse effect
The absorption of heat by gases in the atmosphere especially carbon dioxide and methane
202
Which fossil fuel generates the least carbon dioxide
Natural gas
203
What are three negatives to nuclear power
Power stations are expensive to build
Expensive to dismantle old power stations or store radioactive waste
Nuclear waste is a health hazard
204
What is a disadvantage of using a dynamo on a bike
When the bike stops the light goes out
205
How much energy is transferred as useful energy to the customer by fossil fuel power stations
About a third
206
What does a transformer do
Changes the voltage of an ac current
207
What is a transformer that increases the current called
A step uv transformer
208
What is a transformer that decreases the power called
A step down transformer
209
Where are step down transformers used
Mains adapters and rechargers for phones and iPods
210
How does the national grid reduce its energy loss as heat through wires
They increase the voltage which reduces the rate of flow ( current) this works because the higher the current the more energy is lost as heat
211
What is the 25,000 volts produced at power stations transformed to
Three
400,000v 275,000v 132,000v
212
Why are voltages reduced at towns and villages.
Step down transformers are used to reduce voltages because high voltages are dangerous for people living in settlements
213
Why are power lines and sub stations dangerous
An electric shock could potentially kill someone who gets too close to the line
214
What is the relationship between the turns on the coils and the voltage
Primary voltage/secondary voltage = turns on primary coil/ turns on secondary coil
So
Vp/vs=np/ns
215
How many turns do step up transformers have on their primary coil compared to their secondary coil
Have more turns on their secondary coil than on their primary coil
216
How many turns do step down transformers have on their primary coil compared to their secondary coil
Have fewer turns on their secondary coil than on their primary
217
At which voltage is energy supplied to to the home
230 v
218
What is current measured in
Amperes
Amps
A
219
How does one measure amps
An ammeter
220
How must an ammeter be connected in a circuit
In series with components
221
What is the unit for potential difference
Volts
| V
222
How do you use a voltmeter in a circuit
| How to place it
In parallel with the component
223
With which equation can you work out electrical power
Power (watt,w)= voltage (volts,v)Xcurrent(ampere,a)
224
What is power
A measure of how quickly energy is transferred
225
What is the unit of power
The watt
226
What is the equation for power ( not electrical)
Power equals energy divided by time
227
What's the equation for the cost of electricity
Cost=power x time x cost of 1 kWh
228
How do you work out pay back time
Payback time= cost of energy saving measure/money saved each year
229
Disadvantages to buying an energy saving device
Three
Initial cost
Use of extra resources to manufacture the new device
Cost of des postal of old device
230
Two advantages of buying an energy saving device
Cost efficiency
Saving energy and resources
231
To remember all the types of energy remember this synonym
```
Most magnetic
Kids kinetic
Hate heat or thermal
Learning light
Gcse gravitational potential. Chemical. Sound. Electrical.
Energyelastic potential
Names nuclear
```
232
What is efficiency
The fraction of energy supplied to a device that is transferred to a useful form
233
What is the equation for efficiency
(Useful energy transferred/energy supplied) x 100
234
How many forms of energy are there
9
235
Which two things produce doc electricity
Batteries
Solar cells
236
What is the image one should see on an oscilloscope for dc current
A straight line above 0
237
What is the uk mains supply's voltage and frequency
230 volts
And 50hz
It has a frequency because it is ac so the current changes direction
The frequency shows how many times
A second the current changes direction
238
What does the oscilloscope reading show for an ac current
Wavy lines like in a wave diagram
239
What is the process of making an electrical current
Induction
We say the current has been induced
240
How to increase and induced current
Move the magnet faster
Use a stronger magnet
Increase the number of turns on the coil
Increase the area of the coil
241
How do large generators produce electricity instead of moving a magnet in and out of wire and why
They spin a coil in a magnetic field or spin the magnet because it is more efficient
242
Give an example of a small electrical generator
A bicycle dynamo
243
What is a generator
A device that turns kinetic energy into electrical energy
244
Generators that are turned directly
Three
Wind turbines
Hydroelectric turbines
Wave and tidal turbines
245
Steps from which electricity is generated by fossil fuels
Four
1 heat is released from the fuel and boils water to make steam
2the steam turns the turbine
3the turbine turns a generator and electricity is produced
4the electricity goes through transformers to produce the correct voltage
246
2 steps in which directly turning generators produce electricity
The turbine is turned a generator
Electricity is produced
247
The movement of energy energy through a fossil fuel burning or nuclear power station
The energy produced by burning fossil fuels is stored in water as steam
The energy in steam is transferred to movement in a turbine
The movement in the turbine is then transferred to electrical energy
248
Where is useful energy lost in a power station
Three
Heat losses to environment largest portion
Used in the power station
Lost in transmission
249
Benefits of renewable energy
Three
Their supply is not limited
No fuel costs
They generate far less pollution than fossil fuels
250
Give five renewable energy resources
Biomass energy. The energy released from wood for example
Solar energy
Water energy. For example wave machines tidal barrages and hydroelectric power
Geothermal
Wind energy
251
Negatives of wind energy
Noisy
Spoil view for people
Electricity generated depends on the strength of wind
No wind no electricity
252
Give 4 non renewable energy sources
Fossil fuels. Coal oil natural gas
Nuclear fuels. Uranium
253
Which fossil fuel produces the most carbon dioxide
Coal
254
Define the greenhouse effect
The absorption of heat by gases in the atmosphere especially carbon dioxide and methane
255
Which fossil fuel generates the least carbon dioxide
Natural gas
256
What are three negatives to nuclear power
Power stations are expensive to build
Expensive to dismantle old power stations or store radioactive waste
Nuclear waste is a health hazard
257
What is a disadvantage of using a dynamo on a bike
When the bike stops the light goes out
258
How much energy is transferred as useful energy to the customer by fossil fuel power stations
About a third
259
What does a transformer do
Changes the voltage of an ac current
260
What is a transformer that increases the current called
A step uv transformer
261
What is a transformer that decreases the power called
A step down transformer
262
Where are step down transformers used
Mains adapters and rechargers for phones and iPods
263
How does the national grid reduce its energy loss as heat through wires
They increase the voltage which reduces the rate of flow ( current) this works because the higher the current the more energy is lost as heat
264
What is the 25,000 volts produced at power stations transformed to
Three
400,000v 275,000v 132,000v
265
Why are voltages reduced at towns and villages.
Step down transformers are used to reduce voltages because high voltages are dangerous for people living in settlements
266
Why are power lines and sub stations dangerous
An electric shock could potentially kill someone who gets too close to the line
267
What is the relationship between the turns on the coils and the voltage
Primary voltage/secondary voltage = turns on primary coil/ turns on secondary coil
So
Vp/vs=np/ns
268
How many turns do step up transformers have on their primary coil compared to their secondary coil
Have more turns on their secondary coil than on their primary coil
269
How many turns do step down transformers have on their primary coil compared to their secondary coil
Have fewer turns on their secondary coil than on their primary
270
At which voltage is energy supplied to to the home
230 v
271
What is current measured in
Amperes
Amps
A
272
How does one measure amps
An ammeter
273
How must an ammeter be connected in a circuit
In series with components
274
What is the unit for potential difference
Volts
| V
275
How do you use a voltmeter in a circuit
| How to place it
In parallel with the component
276
With which equation can you work out electrical power
Power (watt,w)= voltage (volts,v)Xcurrent(ampere,a)
277
What is power
A measure of how quickly energy is transferred
278
What is the unit of power
The watt
279
What is the equation for power ( not electrical)
Power equals energy divided by time
280
What's the equation for the cost of electricity
Cost=power x time x cost of 1 kWh
281
How do you work out pay back time
Payback time= cost of energy saving measure/money saved each year
282
Disadvantages to buying an energy saving device
Three
Initial cost
Use of extra resources to manufacture the new device
Cost of des postal of old device
283
Two advantages of buying an energy saving device
Cost efficiency
Saving energy and resources
284
To remember all the types of energy remember this synonym
```
Most magnetic
Kids kinetic
Hate heat or thermal
Learning light
Gcse gravitational potential. Chemical. Sound. Electrical.
Energyelastic potential
Names nuclear
```
285
What is efficiency
The fraction of energy supplied to a device that is transferred to a useful form
286
What is the equation for efficiency
(Useful energy transferred/energy supplied) x 100
287
How many forms of energy are there
9
288
Life cycle of a massive star
Five
Nebula
Massive star
Red super giant
Supernova
Either neutron star or black hole
289
Life cycle of a normal star
Five
Stable stage
Dying star
Red giant
Planetary nebula
White dwarf
Black dwarf
290
What are the two lenses on a refractive telescope called
Objective lens
Focus' the light
Eyepiece lens
Magnifies the light
291
Parts of a reflective lens
2 mirrors
1 lens
292
What are the uses of gamma rays
To sterilise food and medical equipment
In scanners to detect cancer
To treat cancer
293
Uses of X-rays
Three
To look inside objects
In airport security scanners
294
Uses of uv
To detect security marks
Inside fluorescent lamps
To detect forged bank notes ( real bank notes have markings which can glow in uv
295
Uses of visible light
Allows us to see
Photography
296
Life cycle of a massive star
Five
Nebula
Massive star
Red super giant
Supernova
Either neutron star or black hole
297
Life cycle of a normal star
Five
Stable stage
Dying star
Red giant
Planetary nebula
White dwarf
Black dwarf
298
What are the two lenses on a refractive telescope called
Objective lens
Focus' the light
Eyepiece lens
Magnifies the light
299
Parts of a reflective lens
2 mirrors
1 lens
300
What are the uses of gamma rays
To sterilise food and medical equipment
In scanners to detect cancer
To treat cancer
301
Uses of X-rays
Three
To look inside objects
In airport security scanners
302
Uses of uv
To detect security marks
Inside fluorescent lamps
To detect forged bank notes ( real bank notes have markings which can glow in uv
303
Uses of visible light
Allows us to see
Photography
