P2-The earth and universe

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  • Created by: Naana
  • Created on: 07-04-14 16:44
What do electromagnetic waves transfer?
Energy
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Which radiation type on the electromagnetic spectrum has the least energy and lowest frequency?
Radio waves
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Which radiation type on the electromagnetic spectrum has the most energy and highest frequency?
Gamma rays
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How is the frequency of EM radiation related to the energy carried by its photons?
The amount of energy carried by a photon depends on the frequency of the radiation. As the frequency increases, the photon energy also increases.
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What does intensity of a beam of EM radiation mean?
How much energy arrives at each square metre of surface per second
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What is ionisation?
When a photon hits an atom or molecules and it has enough energy to remove an electron and change the atom. Ionising requires a lot of energy.
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Name the three types of ionising radiation
Ultraviolet, x-rays and gamma rays
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Why is ionisation dangerous if it occurs in your cells?
If your cells are exposed to ionising radiation, the damage to DNA molecules can cause mutations and the cells might start dividing over and over again, without stopping-cancer.Or high doses of ionising radiation can kill your cells altogether
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How do radiographers protect themselves from X-rays?
They wear lead aprons as lead absorbs x-rays and they stand behind concrete to protect themselves
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What sort of radiation is used in convection cookers?
Microwaves
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Briefly explain how microwaves cook food
Microwaves make particles vibrate, heating them up. Some microwaves are strongly absorbed by water molecules and things containing water, including all food substances as they have water
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Name 3 greenhouse gases
Carbon dioxide, methane and water vapour
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Describe the greenhouse effect
The sun emits EM radiation which is absorbed by the earth, which warms earth’s surface. Then earth emits some EM radiation (mostly heat) back out. However, the greenhouse gases help keep some of the heat on the earth by acting as an insulating layer
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How is ozone made in the atmosphere?
Ozone which is 3 oxygen atoms joined together, occurs when UV radiation splits an oxygen molecule into 2 oxygen atoms and then one of these oxygen atoms combine with another oxygen molecule to form an ozone molecule
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What happens when an ozone molecule absorbs UV radiation?
It splits back into an oxygen molecule and an oxygen atom-reversible reaction
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Why is the ozone layer important?
Because it protects us from too much UV radiation from the sun which is harmful to humans
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How is carbon dioxide returned to the atmosphere in the carbon cycle?
Respiration in plants, animals and decomposers. Burning of coal and trees. Photosynthesis in green plants and other organisms.
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What has caused the carbon dioxide levels rising dramatically over the last 150 years?
The high demand of energy for electricity and petrol got by burning fossil fuels which released co2. Chopping and burning trees to provide more land for rising population.
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What 2 effects does chopping down and burning trees have on the atmospheric carbon dioxide levels?
Fewer trees mean less co2 taken out of the atmosphere as plants are the main things that take co2 from the atmosphere. Burning trees adds lots of co2 into the atmosphere
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What is global warming?
This is a type of climate change
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What is causing global warming?
The rise in co2 levels is causing global warming by increasing the greenhouse effect
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Give 2 possible consequences of global warming
Negatively affect food production as some regions are too dry or too wet to grow food. Result in flooding because as the sea gets warmer, it expands and sea levels rises
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Why are radio waves good at transmitting information over long distances?
Because they don’t get absorbed by the earth’s atmosphere as much as the rest do
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Give 2 uses of microwaves
For satellite and mobile phone communication
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What advantages do digital signals have over analogue signals?
Digital signals are much higher quality as the information received is the same as the original, and the amount of information stored is higher. Can transmit several signals at once using just one cable or EM wave. Easy to process using computers
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Other cards in this set

Card 2

Front

Which radiation type on the electromagnetic spectrum has the least energy and lowest frequency?

Back

Radio waves

Card 3

Front

Which radiation type on the electromagnetic spectrum has the most energy and highest frequency?

Back

Preview of the front of card 3

Card 4

Front

How is the frequency of EM radiation related to the energy carried by its photons?

Back

Preview of the front of card 4

Card 5

Front

What does intensity of a beam of EM radiation mean?

Back

Preview of the front of card 5
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