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17 Cards in this Set
- Front
- Back
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Where does nuclear radiation come from? |
Nuclear radiation comes from the nucleus of an atom.
Substances that give out radiation are said to be radioactive. |
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State the three types of nuclear radiation. |
alpha beta gamma. |
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What is used to detect nuclear radiation? |
Nuclear radiation can be detected using a Geiger counter.
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Explain background radiation. |
Radiation is all around us. It comes from radioactive substances including the ground, air, building materials and food.
Radiation is also found in cosmic radiation from space. |
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What is the largest source of background radiation? |
Some rocks contain radioactive substances that produce a radioactive gas called radon. |
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Radiation can be absorbed by substances in its path.The thicker the substance, the more the radiation is absorbed. Describe how the three types of radiation penetrate materials in different ways. |
Alpha radiation can be stopped by a sheet of paper. Beta radiation can penetrate air and paper, but is stopped by a few millimetres of aluminium. Gamma radiation can only be stopped by a few centimetres of lead, or many metres of concrete. |
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Describe Alpha radiation. |
Alpha radiation consists of alpha particles. An alpha particle is identical to the nucleus of a helium atom, which comprises two protons and two neutrons. |
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Describe Beta radiation. |
Beta radiation consists of high energy electrons emitted from the nucleus. These electrons have not come from the electron shells or energy levels around the nucleus. Instead, they form when a neutron splits into a proton and an electron.
The electron then shoots out of the nucleus at high speed, leaving the new proton behind in the nucleus. |
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Describe Gamma radiation. |
Gamma radiation is very short wavelength, high frequency electromagnetic radiation. This is similar to other types of electromagnetic radiation, such as visible light and X-rays, which can travel long distances. |
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What is the difference between an alpha particle and a helium atom? |
Two electrons. |
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Radon causes most of our background radiation. Where does radon come from? |
Naturally occurring in rocks. |
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Use the periodic table to work out what uranium-234 becomes if it gives out an alpha particle.
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Thorium-230. |
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What type of particle does a beta particle have the same mass and charge as? |
An electron. |
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Some students describe alpha emission as making the atoms ‘move down the periodic table’ and beta emission as making the atoms ‘go back up’. Explain what they mean. |
Alpha particle emission reduces the atomic number and beta particle emission increases it. |
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A Geiger counter can be used to measure how radioactive a source is.
Why is this not the same thing as measuring the total amount of radiation that a source is emitting? |
Only the radiation that enters the counter is counted; more than half the radiation will miss the counter. |
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Uranium-238 decays into thorium. Thorium decays into protactinium, which decays back to uranium again. Use the periodic table to find out what particles are being emitted and what mass numbers are involved for these elements. |
Uranium-238 gives out an alpha particle and thorium-234 is produced. Thorium-234 gives out a beta particle and protactinium-234 is produced. Protactinium-234 also gives out a beta particle and uranium-234 is produced. |
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What are the key points to remember? |
The radioactivity of a source is unaffected by any physical condition we can control. Radioactivity is a property of the atomic nucleus. There is background radiation around us all the time, and most of it occurs naturally. Oneelement can change into another by alpha or beta emission. |
