Radiation and its risks Flashcards
What is Irradiation
When an object or person is exposed to nuclear radiation. They do not become radioactive so count rate returns to normal when source is put away
What is Contamination
When radioactive isotopes get into places where they destroy cells and tissue
what are doses of radiation measured in
millisieverts (msv) if the dose is really high then it’s measured in sieverts (Sv) and if the dose is lower than a (msv) then we measure in micro sieverts (usv).
what would a low dose of radiation be
less than 10msv
what would a moderate dose of radiation be
less than 100msv
what would a high dose of radiation be
4000msv. Fatal
what happens when an electron goes down a shell
the atom absorbs radiation
what happens when an electron goes up a shell
the atom emits radiation
what are radioisotopes
and why can they emit radiation particles
radioisotopes are elements with an unstable nucleus.
Forces are weak between particles in an unstable nucleus so nuclear radiation particles can be emitted and nuclear radiation causes ionisation
what is alpha radiation
Alpha radiation is a radiation with a symbol that looks like an A its an atom with 4 neutrons And 2 protons the nucleus ejects 2 protons and 2 neutrons it can only travel through 2 or 3 cm in the air and can be stopped by paper also the ionisation power is high.
what is beta radiation
Beta radiation has a symbol that looks like a B. It’s a fast-moving electron it ejects electrons because a neutron can split into a proton plus an electron shooting out the electrons the electron travels 50 cm in the air and can get stopped by 2 or 3mm of aluminium
the ionising power is medium
what is gamma radiation
gamma Radiation has the symbol of a upside down cursive L its an electromagnetic wave The nucleus gets rid of excess energy by emitting a wave. travels 2 or 3 m in the air and is stopped by thick led
what is a half life
Half-life is the time it takes for half of the unstable nuclei in a sample to decay or for the activity of the sample to halve or for the count rate to halve.
The half-life of a radioactive source is 40hr. There are initially 3 million radioactive nuclei in the sample. How many nuclei will remain after 5 days?
375,000
