Radiation and life

Question 1

The definition of Iodising radiation

Answer 1

radiation consisting of particles, X-rays, or gamma rays with sufficient energy to cause ionization in the medium through which it passes.

Question 2

The definition of non Iodising radiation

Answer 2

Radiation with not enough energy to cause ionisation to the absorber

Question 3

Materials are heated when they absorb

Answer 3

electromagnetic radiation of any type.

Question 4

What speed does electromagnetic radiation travel at in a vacuum?

Answer 4

Electromagnetic radiation travels at 300 000km/s in a vacuum.

Question 5

What are the ‘packets’ of energy in a beam of electromagnetic radiation called?

Answer 5

Photons

Question 6

Why does ionising radiation cause chemical reactions when it is absorbed?

Answer 6

Ionising radiation causes chemical reactions because the radiation heats up the absorber.

Question 7

Why are microwave ovens safe to use?

Answer 7

Microwaves are reflected by the metal sides and door screen

Question 8

Some signals are made of a series of pulses which are just off or on. These are called…

Answer 8

digital signals

Question 9

The amount of information needed to store information is measured in…

Answer 9

bytes

Question 10

Signals can pick up random additions on their way to the receiver, making the quality poorer. What word is used for these ‘random additions’?

Answer 10

noise

Question 11

The rainbow pattern produced when white light shines through a prism is called the…

Answer 11

visible spectrum.

Question 12

put these types of electro magnetic radiation in order of highest frequency to lowest:

visible light
microwaves
infrared radiation
x-rays
radio waves
gamma radiation
ultraviolet radiation

Answer 12

gamma radiation	
x-rays		
ultraviolet radiation	
visible light		
infrared radiation	
microwaves	
radio waves

Question 13

Photons deliver different quantities of energy, with radi

o photons delivering the smallest amount, and gamma photons delivering the greatest amount of energy.

Answer 13

The photons deliver different quantities of energy, with radio photons delivering the smallest amount, and gamma photons delivering the greatest amount of energy.

A higher frequency of electromagnetic radiation means more energy is transferred by each photon.

If the photons have enough energy, they can break molecules into bits called ions. This is called ionisation. These types of radiation are called ionising radiation. This radiation can remove electrons from atoms in its path.

In the electromagnetic spectrum only the three types of radiation, which have the photons

Question 14

The intensity of electromagnetic radiation is the energy arriving … … …….. ……. … ……… …. …….. This depends on two things. What are they?

Answer 14

he intensity of electromagnetic radiation is the energy arriving at a square metre of surface each second.
It depends on the energy in each photon, and the number of photons arriving each second.

Question 15

To have the same intensity, a beam of red light would need how many times as many photons as a beam of ultraviolet?

Answer 15

To have the same intensity, a beam of red light would need ten times as many photons as a beam of ultraviolet,

Question 16

How do all forms of electromagnetic radiation deliver energy? The amount of heating depends on what?

Answer 16

All forms of electromagnetic radiation deliver energy. This will heat the material that absorbs the radiation. The amount of heating depends on the intensity of the radiation, and also the length of time the radiation is absorbed for.

Question 17

How does Microwaves heat materials such as food ?

Answer 17

The molecules in the material absorb the energy delivered by the microwaves. This makes them vibrate faster, so the material heats up.

Question 18

What are the ways that Information such as computer data can be transmitted?

Answer 18

Information such as computer data can be transmitted in a number of ways, including via waves and also analogue and digital signals. Infrared light, microwaves and radio waves are all used to transmit information such as computer data, telephone calls and TV signals.

Question 19

Microwave radiation can be used to transmit signals to mobile phone calls through what means? Certain microwave radiation wavelengths pass through the Earth’s atmosphere and can be used to transmit information to and from what?

Answer 19

Microwave radiation can be used to transmit signals such as mobile phone calls. Microwave transmitters and receivers on buildings and masts communicate with the mobile telephones which are in their range.

Certain microwave radiation wavelengths pass through the Earth’s atmosphere and can be used to transmit information to and from satellites in orbit.

Question 20

Radio waves are used for what ?

Answer 20

Radio waves

Radio waves are used to transmit television and radio programmes. Longer wavelength radio waves are reflected from an electrically charged layer of the upper atmosphere. This means they can reach receivers that are not in the line of sight because of the curvature of the Earth’s surface.

Question 21

Why can digital information be more effective than analogue?

Answer 21

Before a sound or piece of information is transmitted, it is encoded in the transmitter in one of the ways described below - analogue or digital. The receiver must then decode the signal to produce a copy of the original information or sound.
Analogue signals vary continuously in amplitude, frequency or both.
Digital signals are a series of pulses with two states - on (shown by the symbol ‘1’) or off (shown by the symbol ‘0’). Digital signals carry more information per second than analogue signals and they maintain their quality better over long distances.

Question 22

All signals become weaker as they travel long distances. They may also pick up ……………. ………… ………… This is called …………, and it is heard as crackles and hiss on radio programmes. Noise may also cause an …………. ……………….to drop, or slow down as the modem tries to compensate.

Answer 22

All signals become weaker as they travel long distances. They may also pick up random extra signals. This is called noise, and it is heard as crackles and hiss on radio programmes. Noise may also cause an internet connection to drop, or slow down as the modem tries to compensate.

Question 23

Describe the effect of noise on Analogue signals

Answer 23

Noise adds extra random information to analogue signals. Each time the signal is amplified the noise is also amplified. Gradually, the signal becomes less and less like the original signal. Eventually, it may be impossible to make out the music in a radio broadcast from the background noise, for example.

Question 24

What is the intensity of electromagnetic radiation ?

Answer 24

The intensity of electromagnetic radiation is the energy arriving at a square metre of surface each second

Question 25

What are the different types of photons?

Answer 25

radio photons and gamma photons

Question 26

What are photons?

Answer 26

Photons deliver different quantities of energy,

Question 27

Photons deliver different quantities of energy, which give the smallers and which the greatest?

Answer 27

Photons deliver different quantities of energy - radio photons deliver the smallest amount, and gamma photons deliver the greatest amount of energy.

Question 28

What does a higher frequency of electromagnetic radiation mean?

Answer 28

A higher frequency of electromagnetic radiation means more energy is transferred by each photon.

Question 29

What is ionisation?

Answer 29

If the photons have enough energy, they can break molecules into bits called ions. This is called ionisation.

Question 30

What is ionising radiation?

Answer 30

This radiation can remove electrons from atoms in its path.

Question 31

Name a gas in the Earth’s atmosphere that absorbs infrared radiation.

Answer 31

carbon dioxide

Question 32

describe the 4 steps of the greehouse effect

Answer 32

1. The Sun’s rays enter the Earth’s atmosphere
2. Heat is emitted back from the Earth’s surface at a lower principal frequency than that emitted by the Sun
3. Some heat passes back out into space
4. But some heat is absorbed by carbon dioxide, a greenhouse gas, and becomes trapped within the Earth’s atmosphere. The Earth becomes hotter.

Question 33

Any process can be thought of in terms of…………….that may affect an ………….
in global warming, one factor is the amount of carbon dioxide in the atmosphere. The outcome is the mean temperature of the atmosphere.

Answer 33

Any process can be thought of in terms of factors that may affect an outcome.

Question 34

in global warming, name one factor and the outcome

Answer 34

Any process can be thought of in terms of factors that may affect an outcome.
in global warming, one factor is the amount of carbon dioxide in the atmosphere. The outcome is the mean temperature of the atmosphere.

Question 35

To establish a correlation between a factor and an outcome, what is needed ?

Answer 35

Convincing evidence - This usually means that enough data must be collected, and that different samples should match

Question 36

A correlation between a factor and an outcome does not mean that the factor causes the outcome. They could both be caused by some other factor. Give an example regarding children with bigger feet.

Answer 36

For example: Children with bigger feet (factor) are, on average, better readers (outcome).

There is another factor which affects both of these things: age. Older children usually have bigger feet, and older children are usually better readers!

Question 37

Radiation that is not absorbed by the atmosphere does what?

Answer 37

Radiation that is not absorbed by the atmosphere reaches the Earth’s surface and warms it, leading to the greenhouse effect.

Question 38

The atmosphere transmits microwaves, and these can be used to do what?

Answer 38

The atmosphere transmits microwaves, and these can be used to communicate with satellites.

Question 39

Any radiation absorbed by living cells can damage them by heating them. However, why are ionising radiations more likely to damage living cells?

Answer 39

This is because photons of ionising radiation deliver much more energy. They can easily kill cells, and can also cause cancer by damaging the DNA in the nucleus of a cell. This is because photons of ionising radiation deliver much more energy.

Question 40

They are not ionising, and so cannot cause cancer in the way that ultraviolet, X-rays or gamma rays do.

Answer 40

They are not ionising, and so cannot cause cancer in the way that ultraviolet, X-rays or gamma rays do.

Question 41

Why can microwaves not escape from the oven?

Answer 41

The microwaves cannot escape from the oven, because the metal case and the metal grid on the door reflect microwaves back into the oven

Question 42

One health risk which is definitely present in our environment is ultraviolet, in sunlight. Not much of the ultraviolet reaching the Earth gets to us, - why?

Answer 42

One health risk which is definitely present in our environment is ultraviolet, in sunlight. Not much of the ultraviolet reaching the Earth gets to us, because the ozone layer high up in the atmosphere absorbs most of it. In the summer, it is wise to use sunscreens and clothing to absorb ultraviolet, and prevent it reaching the sensitive cells of the skin.

Question 43

How does the ozone layer absorb ultraviolet ? Is this reversible?

Answer 43

The ozone layer absorbs ultraviolet because ultraviolet ionises the ozone, which then changes to oxygen. This chemical change is reversible, and the oxygen changes back to ozone.

Question 44

What are the harmful affects of Chemicals used in aerosol spray cans and fridges ?

Answer 44

Chemicals used in aerosol spray cans and fridges gradually made their way up to the ozone layer when released into the atmosphere, and removed some of it. This has increased the intensity of the ultraviolet radiation reaching the Earth

Question 45

What are the risks and benefits of ultraviolet ?

Answer 45

some ultraviolet is good for you, as it produces vitamin D in the skin

Question 46

A higher frequency of electromagnetic radiation means what?

Answer 46

A higher frequency of electromagnetic radiation means more energy is transferred by each photon.

Question 47

What is ionisation?

Answer 47

If the photons have enough energy, they can break molecules into bits called ions. This is called ionisation. These types of radiation are called ionising radiation. This radiation can remove electrons from atoms in its path.

In the electromagnetic spectrum only the three types of radiation, which have the photons

Question 48

What has happened in the last 200 hundred years to the carbon cycle?

Answer 48

For thousands of years, the processes in the carbon cycle were constant, so the percentage of carbon dioxide in the atmosphere did not change. Over the past 200 years, the percentage of carbon dioxide in the atmosphere has increased steadily because humans are:
burning more and more fossil fuels as energy sources
burning large areas of forests to clear land, which means that there is less photosynthesis removing C02

Question 49

how is Infrared light transmitted?

Answer 49

Information such as computer data and telephone calls can be converted into infrared signals and transmitted by optical fibres.

Question 50

What is the advantages of optical fibre?

Answer 50

Optical fibres are able to carry more information than an ordinary cable of the same thickness. In addition the signals they carry do not weaken so much over long distances.

Question 51

how do Television remote controls work?

Answer 51

Television remote controls use infrared light to transmit coded signals to the television set in order to, for example, change channels or adjust the volume.

Question 52

An important advantage of digital signals over analogue signals as regards noise is what?

Answer 52

An important advantage of digital signals over analogue signals is that if the original signal has been affected by noise it can be recovered more easily. In analogue signals, when the signal is amplified to return to its original height, noise gets amplified as well.

Question 53

name some other greenhouse gases?

Answer 53

Water vapour and methane

Question 54

Why is methane effective?

Answer 54

Even though methane is present in trace (tiny) amounts only, it is a very efficient absorber of infrared.

Question 55

A beam of microwaves would need how many times as many photons to be as intense as a beam of ultraviolet?

Answer 55

a beam of microwaves would need a million times as many.

Question 56

Global warming could cause what?

Answer 56

Global warming could cause:
climate change
extreme weather conditions in some areas.

Question 57

what provides evidence to support the view about global warming?

Answer 57

One piece of evidence that supports the view of scientists who blame human activities for global warming has been provided by ‘supercomputers’. Computer generated climate models, based on different amounts of carbon dioxide in the atmosphere, produce the same changes as have been observed in the real world.

Question 58

What could cause rising sea levels and the flooding of low-lying land?

Answer 58

Melting polar ice, and the thermal expansion of sea water, could cause rising sea levels and the flooding of low-lying land.

Question 59

Extreme weather events become more likely due to what?

Answer 59

Extreme weather events become more likely due to increased convection accompanied by more water vapour being present in the hotter atmosphere.

Question 60

Describe one piece of evidence that supports the view of scientists who blame human activities for global warming ?

Answer 60

One piece of evidence that supports the view of scientists who blame human activities for global warming has been provided by ‘supercomputers’. Computer generated climate models, based on different amounts of carbon dioxide in the atmosphere, produce the same changes as have been observed in the real world.

Question 61

What sort of questions do you need to ask when looking at graphs to establish correlation and cause?

Answer 61

consider these questions:
are the changes reported significantly large?
are they properly matched in terms of the times over which they are reported?
do these two graphs match well enough?

Question 62

The ideas of correlation and cause are illustrated with the evidence for global warming.
How?

Answer 62

To investigate the relationship between a factor and an outcome, it is important to control all other factors that may affect the outcome.

Other factors affecting global warming

Another factor that may affect the mean temperature of the atmosphere is the amount of energy given out by the Sun. Most scientists agree that this has not changed in the past 200 years

There are some scientists who agree that global warming is taking place, but do not agree that carbon dioxide levels are to blame.

Once experiments have shown that there is a definite correlation between a factor and an outcome, it is still not enough to prove that the factor causes the outcome.

For this to be proven, there must be some scientific explanation of how the relationship can happen.
for carbon dioxide and global warming, the explanation is that carbon dioxide is a greenhouse gas. It absorbs infrared given off by the warm Earth, and this infrared cannot then escape into space. This keeps the Earth warmer than it would be if the carbon dioxide did not absorb so much infrared.

Question 63

Information such as computer data and telephone calls can be converted into infrared signals and transmitted by by what

Answer 63

optical fibres. .

Question 64

How does a Longer wavelength radio work?

Answer 64

Longer wavelength radio waves are reflected from an electrically charged layer of the upper atmosphere. This means they can reach receivers that are not in the line of sight because of the curvature of the Earth’s surface.

Question 65

describe the effect of noise on Digital signals

Answer 65

Noise also adds extra random information to digital signals. However, this noise is usually lower in amplitude than the ‘on’ states of the digital signal. As a result, the electronics in the amplifiers can ignore the noise and it does not get passed along. This means that the quality of the signal is maintained. This is one reason why television and radio broadcasters are gradually changing from analogue to digital transmissions.

Question 66

What are the advantages of digital?

Answer 66

They can also squeeze in more programmes because digital signals can carry more information per second than analogue signals. Another advantage of digital signals is that information can be stored and processed by computers.

Question 67

Does the atmosphere absorb all radiation?

Answer 67

Some radiation of the electromagnetic spectrum is absorbed by the atmosphere, but some is transmitted.

Question 68

which waves pass through the atmosphere?

Answer 68

Light, some infrared, some ultraviolet, and microwaves, pass through the atmosphere and reaches the Earth’s surface.

Question 69

Which do not reach the earth’s surface?

Answer 69

Gamma rays, X-rays, most of the ultraviolet and some of the infrared are absorbed by the atmosphere and do not reach the Earth’s surface.

Question 70

what is the greenhouse effect?

Answer 70

Infrared from the Sun reaches the Earth’s surface and warms it.

The warm Earth emits some infrared radiation, and some of this is absorbed by gases in the atmosphere. This is called the greenhouse effect. If there was no greenhouse effect, the Earth would be too cold for life as we know it.

Question 71

why is Photosynthesis?

Answer 71

Light from the Sun reaching the Earth’s surface provides the energy for plants to produce food by photosynthesis.

Photosynthesis replaces carbon dioxide in the atmosphere with oxygen. This reverses the process of respiration.

Question 72

what are the risks from ultraviolet?

Answer 72

Some radiation, such as ultraviolet, exposes our skin to harmful rays and puts us at risk of developing skin cancer.

Question 73

why has the percentage of carbon dioxide changed?

Answer 73

For thousands of years, the processes in the carbon cycle were constant, so the percentage of carbon dioxide in the atmosphere did not change. Over the past 200 years, the percentage of carbon dioxide in the atmosphere has increased steadily because humans are:
burning more and more fossil fuels as energy sources
burning large areas of forests to clear land, which means that there is less photosynthesis removing C02

Question 74

What is the scientific argument about global warming?

Answer 74

There are some scientists who agree that global warming is taking place, but do not agree that carbon dioxide levels are to blame.

Once experiments have shown that there is a definite correlation between a factor and an outcome, it is still not enough to prove that the factor causes the outcome.

For this to be proven, there must be some scientific explanation of how the relationship can happen.
for carbon dioxide and global warming, the explanation is that carbon dioxide is a greenhouse gas. It absorbs infrared given off by the warm Earth, and this infrared cannot then escape into space. This keeps the Earth warmer than it would be if the carbon dioxide did not absorb so much infrared.

Question 75

To investigate the relationship between a factor and an outcome, it is important to do what?

Answer 75

To investigate the relationship between a factor and an outcome, it is important to control all other factors that may affect the outcome.