The time it takes for half the radioactive nuclei to decay
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what is radioactive decay?
when an unstable nucleus emits a type of radiation
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what is an alpha particle?
A helium nucleus (2 protons + 2 neutrons)
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what is a beta particle?
A high speed electron made when a neutron turns into a proton
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what is a gamma ray?
an electromagnetic wave
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which types of radiation is the most/ least ionising?
most: alpha
least:gamma
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which types of radiation are the most/ least penetrating?
most: gamma
least: alpha
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what happens to an atoms atomic mass and atomic number with gamma radiation?
nothing/ no change
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what happens to an atoms atomic mass and atomic number with beta radiation?
atomic mass: remains the same
atomic number:rises by 1 (a proton is created)
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what happens to an atoms atomic mass and atomic number with alpha radiation?
atomic mass: decreases by 4
atomic number: decreases by 2
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what is the rate of radioactivity measured in?
becquerels (Bq)
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what does 1 becquerel represent?
1 decay per second
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what is used (equipment) to measure radiation?
Geiger meter/ Geiger-Muller tube
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what is irradiation?
when someone or something is exposed to something radioactive (that is in the general vicinity) but does not become radioactive (only causes a low dose)
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what is contamination?
when radioactive particles escape in to the environment (causes a high dose)- the unwanted presence of radioactive material (e.g. when a person comes into direct contact with nuclear radiation)
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How is irradiation used (give 2 examples)?
To sterilise medical equipment OR to preserve fruit
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what is 1 advantage and 1 disadvantage of irradiating things?
You are able to sterilise (kill bacteria) without using high temperatures so you can use it on things that would normally melt
BUT
it can be harmful to the sterilisers (people doing it)
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what are three examples of background
radiation?
rocks, sun, food
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why is radiation dangerous?
it can cause cell mutations and cancer
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what is a peer review?
when a scientist work is published (shared with other scientists) and checked
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what can alpha particles be stopped by?
a single sheet of paper
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what can stop beta particles?
several meters of air or 5 mm of aluminium
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what can stop gamma radiation (waves)?
thick sheets of lead or multiple meters of concrete
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what is the final type of radiation that could occur to try and stabilize a nucleus?
release of a neutron
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which 3 things determine how harmful radiation is?
-type of radiation
-amount of radiation
-where you get exposed to it
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what precautions can be taken when being exposed to radiation?
-wearing protective clothing (gloves, overalls, etc.)
-keeping it in a lead lined box
-using equipment like tongs to handle it
-reducing the amount of time spend exposed
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Other cards in this set
Card 2
Front
what is radioactive decay?
Back
when an unstable nucleus emits a type of radiation
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