The decay of radioactive materials by the emission of either Alpha radiation, Beta radiation or Gamma Radiation;
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What occurs during Alpha emission?
The radioactive decays emitting an alpha particle (A helium nucleus made up of two protons and two neutrons) The atomic number of this atom will have decreased by two and the mass number by four.
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What is radiation measured in?
Number of nuclear decays emitted per second.
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Why is alpha radiation highly ionising?
Because it is missing two electrons and has a 2+ electric charge, therefore it attracts electrons away from atoms as they pass, giving them a positive charge.
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What occurs during Beta emission?
The radioactive atom decays by changing a neutron into a proton and an electron. An electron is ejected from the nucleus. The atomic number of the original particle will have increased
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What is a half life?
The time it takes for half of the nuclei in a radioactive substance to decay.
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How is it possible to date rocks?
Measuring the proportion of uranium and lead in the rock and knowing the half life of uranium.
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How can half-life be calculated?
By using a table or graph.
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What is background radiation?
Radiation that occurs naturally in our environment and is all around us.
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What is background radiation released by?
Radioactive substances in soil and rocks, cosmic rays from outer space and some man-made sources and waste products.
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What are tracers?
Radioisotopes that are used to track the dispersal of waste, find leaks and blockages in underground pipes and find the routes of underground pipes.
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What radioactive material is used in tracing and why?
Gamma Radiation as it can penetrate through the soil to the surface.
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How does tracing work?
A material that emits gamma rays is put into the pipe and is tracked by a detector through the pipe. If the radioactive material escapes, there is a leak and if the material stops there will be a blockage.
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How is Alpha Radiation used in smoke detectors?
Alpha causes air particles to ionise, which are then attracted to oppositely charged electrons in the smoke detector. This results in a flow of electric current. Smoke triggers the alarm because alpha cannot pass through it and the current decreases.
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How can carbon-14 be used to date once-living materials?
The amount of carbon-14 in the atmosphere has remained the same over thousands of years and so, the amount of decayed radioactive carbon-14 can be used to age once-living things.
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How can Gamma Rays be used to treat cancer?
Gamma rays are concentrated at the point where the tumor is to destroy it. This is called Radiotherapy.
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What are tracers when used in the body?
Small amounts of radioactive material which are swallowed or injected into the patient and then the tracer is tracked through the body to detect problems.
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What can X-rays be used for?
Building a picture of the inside of a patients body.
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What other things in medicine can Gamma Radiation be used for?
Sterilize medical equipment.
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Why can't alpha be used as a medical tracer?
As it cannot pass through the skin.
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Other cards in this set
Card 2
Front
What occurs during Alpha emission?
Back
The radioactive decays emitting an alpha particle (A helium nucleus made up of two protons and two neutrons) The atomic number of this atom will have decreased by two and the mass number by four.
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