Ioactivity Flashcards
What does a nuetron decay into
proton, electron, anti electron neutrino
Why is an anti electron neutrino given out in the decay of a nuetron?
Lepton number must be conserved
What is radioactive decay?
random, spontaneous
What is the activity of a source?
Rate at which nuclei decay, number of decays per second
What is the decay constant
Probability of an individual nucleus decaying per unit time
Why does background radiation exist?
cosmic rays, naturally occurring radioactive compounds / anthropogenic sources (nuclear power plants)
What units does activity have
Bq (s to the minus one)
What same base units does bq have?
Hertz
How are things craving dated?
Ratio of C12 to C14 in the atmosphere is known. Living organisms absorb C14 during their lives - this is capped amount at death. C14 is a radioactive isotope decays through beta emission (half life 5700 years). Comparison of ratios of carbon quantities
What happens in the dating of organisms older than 5700 years?
The amount of C14 becomes immeasurably small - hence rubidium is often used instead
What is the carbon ratio of 12 to 14 affected by?
emissions from fossil fuels, volcanic eruptions, deforestation
What is a limitation of carbon dating
Activity of C14 is so low it’s difficult to differentiate from background radiation
What is the range of beta plus
Very short as - annihilate with matter very quickly
What is alpha radiation stopped by?
Paper
What is beta radiation stopped by?
a few millimetres of aluminium
