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28 Cards in this Set
- Front
- Back
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What is type of radiation is light? |
Electromagnetic (EM) |
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What is radiation? Give an example. |
Radiation is just a transfer of energy i.e sunlight is a transfer of energy from the Sun to the Earth. |
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What is visible light? |
Radiation that our eyes can detect. |
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What are the seven types of radiation that make up the electromagnetic spectrum? |
Radio Waves Microwaves Infrared Visible Light Ultra violet X rays Gamma rays |
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Why can we feel the warmth of the sun? |
Because heat energy from the sun is travelling through space as infrared radiation. |
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What is energy delivered as? |
Photons |
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What is a photon? |
a photon is a tiny 'droplet' or 'package' of energy. |
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What does the amount of energy that a photon caries depend on? |
the frequent of radiation. As you get further right in the Electromagnetic scale the energy and frequency increases. |
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What is emitted from an object that increases with temperature? |
The frequency of heat (thermal) |
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What speed do all types of EM (Electromagnetic) waves travel at through a vacuum (space) once they have been emitted? |
The speed of light. |
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What is the speed of light? |
300 000 km/s or 3.0 X10(To the power of eight) m/s |
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What happens when radiation is emitted? |
It spreads out until it reaches some matter (a substance-like air, glass, walls...) |
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What three things can happen once radiation had been emitted? |
The radiation might be transmitted It could be reflected The radiation could be absorbed. |
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What causes one of three effects to occur once radiation has been emitted? |
What happens depends on the what the substance is like and they type of radiation. |
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What two things happen when sunlight shines on glass? |
When sunlight shines on glass some of it is transmitted, but some of it is reflected. |
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What emits infrared radiation, how far does it travel and what happens to it? |
infrared radiation is emitted from the sun and travels 150 000 000 km through space, to Earth Some of it is then absorbed or reflected by the atmosphere- but some of it reaches objects such as cars and warms the up. |
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What is a detector and give one example? |
Objects that can absorb radiation are called detectors- our eyes are light detectors for instance. |
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What do photons do when radiation is absorbed by matter? |
Photons transfer their energy to the matter.
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What equation can we do to figure out the total energy transferred from photons? |
Total energy = number of photons x energy of each photon |
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What do we mean by the intensity (or strength) of radiation? |
How much energy arrives at each square metre of surface per second. |
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What are the unit of intensity? |
W/m(squared) - watts per metre squared. |
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why does the intensity of a beam of radiation decrease? |
The intensity of a beam of radiation decreases with distance from the source because: The beam spreads out the beam gets partially absorbed as it travels |
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Why is the intensity of infrared radiation less intense on Earth than it would due on a planet such as mercury? |
As infrared radiation from the sun travels through space and the atmosphere, it spreads out and some of it is absorbed or reflected back by the atmosphere. |
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What is ionisation? |
When a photon hits an atom or molecule, it sometimes has enough energy to remove an electron and change an atom or molecule. |
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What can the changed atoms or molecules start after ionisation? |
The hanged atoms or molecules can go on to initiate (start) other chemical reactions. |
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What does it take a lot of to remove an electron from an atom or molecule? |
Energy. |
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What types of radiation can cause ionisation? |
Only types of energy with a high enough proton energy can cause ionisation because they need a lot of energy in order to remove an election from an atom or molecule. |
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Name the 3 types of radiation that can cause ionisation? |
Ultra violet X- rays gamma rays |
