Atoms and Nuclear Radiation Flashcards
state what is meant by radioactive decay
the nuclei of some atoms are unstable and to become more stable they give out radiation
state what is meant by activity
the rate at which a source of unstable nuclei decays
state what is meant by count rate
number of decays recorded each second by a detector
state the different penetration levels of alpha beta and gamma
alpha - easily stopped by a few sheets of paper
beta - penetrates paper but stopped by a thin sheet of aluminium
gamma - only stopped by thick lead or several metres of concrete
state the different speeds of alpha beta and gamma
alpha - slowest
beta - medium
gamma - fastest
state the different ranges in air of alpha beta and gamma
alpha: 6-8cm
beta: 1-2m
gamma: 300-500m
state the different ionising powers of alpha beta and gamma
alpha: high
beta: medium
gamma: low
explain what is meant by the half-life of a radioactive isotope
the time it takes for the number of nuclei of the isotope in the sample to half.
explain what is meant by irradiation
when an object or person is exposed to radiation. protection from irradiation means stopping the radiation from reaching you
state what is meant by contamination
where a radioactive source is in contact with an object or person. the radioactive substance rather than the emissions are present
state what is meant by background radiation
the constant low level radiation in the environment
this can be radiation from rocks, building materials or cosmic rays
radioactive pollution from nuclear testing and medical waste also contributes to background radiation
