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Core Science Flashcards

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Physics 101 flashcards AP® Physics flashcards
1
Q

What is the geocentric model?

A

It has the earth at the centre

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2
Q

Describe the heliocentric model?

A

The sun is at the centre

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3
Q

Who put forward the heliocentric model?

A

Copernicus

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4
Q

When was the telescope invented?

A

16th Century

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5
Q

What do telescopes allow?

A

The naked eye to view things in great detail

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6
Q

What did Galileo discover?

A

4 of Jupiters moons

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7
Q

What have photographs allowed?

A

For detailed images of space to be produced

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8
Q

What is refraction?

A

When light crosses a boundary and changes speed and therefore direction

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9
Q

A line at a right angle to the interface is the what?

A

Normal

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10
Q

What do convex lenses do?

A

They cause light rays to converge and form an image

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11
Q

What is the point called where the image focuses?

A

Focal point

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12
Q

What is the distance between the lens and the focal point?

A

The focal length

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13
Q

How do refracting telescopes work?

A

A convex lens (the objective lens) creates the image and the eyepiece lens magnifies it

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14
Q

As well as refract, waves also do what at a boundary?

A

They are reflected

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15
Q

In order for a reflecting telescope to have a large magnification, what do they need to be?

A

Long

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16
Q

What are the disadvantages of large lenses?

A

They are very heavy and difficult to make in the correct shape therefore colours can be distorted

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17
Q

What does the primary mirror do?

A

Focuses the rays

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18
Q

What does the secondary mirror do

A

It reflects the rays to the eye piece lens

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19
Q

What do sea waves do when they hit the shore or a cliff?

A

They transfer energy

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20
Q

What type of waves oscillate at right angles to the direction of the wave?

A

Transverse

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21
Q

What group of waves are all transverse?

A

Electromagnetic

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22
Q

Describe the movement of longitudinal waves

A

The move back and forth in the direction of the wave (in compressions and expansions)

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23
Q

What is frequency?

A

How many waves pass per second

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24
Q

What is frequency measured in?

A

Hertz

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25
Q

What is wavelength?

A

The distance between waves

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26
Q

What is wavelength measured in?

A

Metres

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27
Q

What is amplitude?

A

The heist of the wave from the rest point

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28
Q

What is wave speed?

A

How fast the wave travels

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29
Q

What are the two equations for working out wave speed?

A

Wave speed = Distance/Time

Wave speed = frequency x wavelength

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30
Q

What do sea waves do when they hit the shore or a cliff?

A

They transfer energy

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31
Q

What type of waves oscillate at right angles to the direction of the wave?

A

Transverse

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32
Q

What group of waves are all transverse?

A

Electromagnetic

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33
Q

Describe the movement of longitudinal waves

A

The move back and forth in the direction of the wave (in compressions and expansions)

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34
Q

What is frequency?

A

How many waves pass per second

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35
Q

What is frequency measured in?

A

Hertz

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36
Q

What is wavelength?

A

The distance between waves

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37
Q

What is wavelength measured in?

A

Metres

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38
Q

What is amplitude?

A

The heist of the wave from the rest point

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39
Q

What is wave speed?

A

How fast the wave travels

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40
Q

What are the two equations for working out wave speed?

A

Wave speed = Distance/Time

Wave speed = frequency x wavelength

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41
Q

Who discovered infrared?

A

Herschel

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42
Q

Describe Herschel’s discovery of infrared?

A

He noticed that different coloured filters heated up his telescope different amounts so he took the temperatures and noticed that the temperature rose yet again beyond the red light and he therefore called this ‘invisible ray’ infrared

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43
Q

Who discovered ultraviolet?

A

Ritter

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44
Q

Describe the discovery of ultraviolet?

A

He noticed that silver chloride turned black faster under violet light, he then showed that it turned black fastest beyond the violet and he named it ultraviolet

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45
Q

Can EM waves travel through a vacuum?

A

Yes

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46
Q

How fast do EM waves travel?

A

300,000km per second

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47
Q

Name the EM waves from shortest wavelength to the longest?

A 
Gamma
X-Ray
Ultraviolet
Visible
Infrared
Microwaves
Radio waves
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48
Q

Why are microwaves dangerous to humans?

A

They can heat water which can be dangerous as our bodies are mostly water

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49
Q

Why is infrared dangerous for humans?

A

It’s absorbed by skin and causes burns

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50
Q

Why is ultraviolet dangerous for humans?

A

Causes damage to DNA which causes cancer

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51
Q

Why’re gamma and X-rays dangerous for humans?

A

They cause mutations in DNA

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52
Q

Name a use of fluorescence

A

It’s used to identify counterfeit bank notes and is sometimes used in security lights

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53
Q

What are X-ray scanners used for?

A

To identify items in luggage

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54
Q

What is infrared used for?

A

It is used for thermal imaging where cctv cameras people who emit infrared

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55
Q

What are radio waves used for?

A

Broadcasting and communications

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56
Q

What are microwaves used for?

A

TV signals and wifi and mobile signals

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57
Q

What is gamma used for?

A

Sterilising food and surgical equipment

58
Q

What is ultraviolet used for?

A

Disinfect water and sewage

59
Q

How is gamma used in diagnosis and treatment of cancer?

A

It is used in radiotherapy and used in tracers

60
Q

What is infrared used in?

A

TVs and optical fibres

61
Q

What is ionising radiation?

A

Radiation that can remove electrons to form ions

62
Q

What is it called when an element emits gamma all the time?

A

It is said to be radioactive

63
Q

What two other things are ionising that isn’t gamma?

A

Alpha and beta particles

64
Q

What kind of rays do telescopes allow for viewing?

A

Visible light

65
Q

What invention has allowed for more data to be gathered? (In terms of space)

A

Photographs

66
Q

What do spectrometers do?

A

Analyse different wavelengths

67
Q

Why can the Hubble produce clearer images than ground telescopes?

A

Because light isn’t reflected through the atmosphere

68
Q

What’s the difference between space probes, landers and rovers?

A

Space probe - satellite that detects temperature and takes photos and then transmits the data back to earth
Lander - lands on the planet and monitors certain things
Rover - can move around the planet and collect samples

69
Q

What does SETI stand for and what is it?

A

Search for extra terrestrial intelligence - they are a series of projects that analyse radio waves to find messages from other intelligent life

70
Q

Describe the stages of the life cycle of an average star

A

Cloud of gas, protostar, average star, red giant, shell of gas, white dwarf, black dwarf

71
Q

What happens when a star becomes a protostar?

A

The cloud has become more dense and heats up and begins to glow

72
Q

How long is an average star stable for?

A

10 billion years - until most of the hydrogen is fused

73
Q

Describe what happens when a star becomes a red giant

A

The star collapses and the outer layer expands

74
Q

What forms the white dwarf?

A

The remains from the shell of gas

75
Q

What are the differences between average star and giant star after the main sequence?

A

A giant star becomes a red supergiant and then a supernova as the outer layers are cast outwards

76
Q

What is the requirements of a star to become a black hole?

A

If the mass after the supernova is 4 times that of the sun, if not it becomes a neutron star (small but very dense)

77
Q

Describe the main points of the Big Bang theory

A

Tiny point of concentrated energy
13.5 billion years ago
Constant expansion

78
Q

Describe the steady state theory

A

New matter is constantly made

Always existed

79
Q

What is cosmic microwave background radiation?

A

It is believed to be left over energy from Big Bang

80
Q

As an emergency vehicle drives past, the pitch gets lower, what is this called?

A

The Doppler effect

81
Q

What does pitch depend on and what happens when a sound source moves?

A

Pitch depends on frequency and wavelength, as the object moves, they are ‘stretched’

82
Q

What happens in red shift?

A

The wavelength of the object is ‘stretched’ making it appear red

83
Q

What is frequency measured in?

A

Hertz

84
Q

All sound waves are ____ and travel in a ___

A

Longitudinal

Medium

85
Q

What is the range that humans can hear?

A

20-20,000Hz

86
Q

Anything below 20Hz us referred to as what?

A

Infrasound

87
Q

What animals use infrasound?

A

Elephants, giraffes and whales

88
Q

Describe 3 uses of infrasound

A

Tracking animal behaviour
Monitoring volcanoes (as they give out IS)
Detection of meteors and meteorites

89
Q

Anything about 20,000Hz is referred to as what?

A

Ultrasound

90
Q

What do bats use ultrasound for?

A

Echolocation

91
Q

What is sonar equipment used for?

A

Detection of ocean depth and fish

92
Q

What is the gel used for in ultrasound baby scans?

A

To prevent the waves reflecting off the skin

93
Q

How is an ultrasound image formed?

A

From the echoes and the time taken

94
Q

What do earthquakes cause the transmission of?

A

Seismic waves

95
Q

What do seismometers used for?

A

To detect seismic waves

96
Q

Where is the focus?

A

The place where the rock moves

97
Q

What is the epicentre?

A

The place directly above the focus

98
Q

Describe the differences between P and S waves

A

P - longitudinal, up and down, faster

S - transverse, side to side

99
Q

How is the rock beneath the Earth’s surface investigated?

A

Through seismic waves and seismometers

100
Q

What happens to the seismic waves when the rock changes?

A

Some will be reflected and some with refract and will then be detected a certain distance away

101
Q

What is triangulation?

A

Working out the epicentre from the reading of 3 seismometers

102
Q

Why do tectonic plates move?

A

Due to convection currents

103
Q

What can sometimes happen if an earthquake happens in the sea?

A

A tsunami

104
Q

Tsunamis can’t be detected through seismometers so what is used instead?

A

Pressure sensors

105
Q

What is electricity?

A

A flow of charged particles

106
Q

What is current?

A

The rate of flowing charge

107
Q

What is voltage?

A

A measure of energy transferred by the charge

108
Q

What do solar cells do?

A

They convert solar energy into electrical energy

109
Q

How does hydroelectricity work?

A

Electricity is generated from falling water in places where water can be trapped in a resovoir

110
Q

What do wind turbines do?

A

They convert kinetic energy into electric energy through the movement of the turbine

111
Q

How does geothermal energy work?

A

Heat is transferred from hot underground rocks to water which turns to steam to turn a turbine

112
Q

How does tidal power work?

A

They generate electricity when turns in a dam turn as the tide flows in and out

113
Q

How does wave power work?

A

When floating generators move up and down they generate electricity, also waves can force air up pipes which turns a turbine

114
Q

Why are nuclear power stations non renewable?

A

Because radioactive metals will run out

115
Q

Fossil fuelled power stations contribute to what two things?

A

Climate change and acid rain

116
Q

Name 3 advantages of non-renewable energy?

A

There is a good supply at the moment
Cheaper than renewable fuel
Don’t depend on weather or tides

117
Q

If you move a wife in a magnetic field, what will flow and what is this called?

A

Electric current

Electromagnetic induction

118
Q

If a current has formed as a result of EM induction, what is the current?

A

An induced current

119
Q

Describe 4 ways a current can be incensed

A

More turns on the coil
Iron core in the coil
Stronger magnets
Moving wire quicker

120
Q

How can the direction of a current be changed?

A

By changing the direction of wire movement and the direction of the magnetic field

121
Q

What do some bikes have to produce electricity in their lights?

A

Dynamos

122
Q

The current in a simple Dynamo only travels in one direction so what does that mean it is?

A

Direct current

123
Q

Describe how an alternating current is induced in a medium sized generator

A

It is transferred through slip rings and carbons brushes (the slip rings prevent wires from tangling)

124
Q

How do generators in power stations induce current?

A

They use electromagnets because strong permanent magnets are too expensive

125
Q

What are electromagnets?

A

They are magnets produced from electricity to create a powerful magnetic field

126
Q

What is the system called that transfers electricity from stations to homes?

A

The national grid

127
Q

Why is the voltage so high on the national grid?

A

To prevent heat energy from being lost in the transmission wires and therefore efficiency is improved

128
Q

What voltage do power stations produce and what is this increased to before being sent around the country?

A

25 KV which is increased to 400 KV

129
Q

What is the role of a step up and step down transformer?

A

Step up - increases voltage/decreases current

Step down - decreases voltage/increases current

130
Q

Describe how a transformer works

A

They consist of 2 coils of wire wound to an iron core. The electricity is supplied to the primary coil and obtained by the secondary coil at a different voltage

131
Q

What is the equation that shows the relationship between voltage in a transformer to the number of turns of coil?

A

Voltage (P) / V (S) = Turns (P) / (S)

132
Q

What is the energy used by an appliance per second?

A

Power, measured in watts

133
Q

What is the name of the rating given to an appliance and what is it measured in?

A

A power rating measured in kilowatts

134
Q

By what measure do electric companies charge electricity use?

A

Kilowatt per hour

135
Q

What is the pricing system used by electricity companies?

A

Pence per 1 KW

136
Q

What is payback time?

A

The amount of time it takes to save the money it costed to buy the item

137
Q

What does the most cost-efficient method do?

A

Saves the most amount of money compared to the cost

138
Q

Name the forms of energy

A

Thermal, light, electrical, kinetic, sound, chemical potential, nuclear potential, elastic potential, gravitational potential

139
Q

What is a system?

A

Something in which we are studying changes

140
Q

Describe the law of conservation of energy

A

It means that energy cannot be destroyed or created

Input energy = output energy

141
Q

What does a sankey diagram show (energy conversion diagram)

A

It shows energy transfers

142
Q

What is efficiency?

A

How good a device is at converting energy into useful forms

Physics (2 decks)

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