P2 - Uses of Radiation Flashcards
what causes nuclear radiation?
an unstable nucleus when it decays
Name the 3 types of radiation
alpha beta gamma
What is ionisation?
when the radioactive atoms lose or gain electrons
What can ionisation intitiate?
other chemical reactions between different atoms
How can radiation affect human cells?
It enters them and can ionise molecules and damage DNA which caues mutations in the cell and can cause cancer. High doses can kill cells completely
What is the ionising power of each kind of radiation?
How far it can penetrate materials and the further it can penetrate before hitting the atom = the less ionising
Describe Alpha particles
Big + heavy, and slow moving ( 2 protons + 2 electrons) due to size they are stopped quickly so dont penetrate far into materials so stopped by paper and skin. Strongly ionising as they knock into atos and knock electrons off before they slow down
Describe Beta particles
Electrons, small and move quite fast. penetrate moderately before colliding = moderately ionising still stopped by thin sheet aluminium
Describe Gamma rays
If the nucleus needs to get rid of extra energy it emits gamma rays - a typpe of em radiation. No mass + no charge. Penetrate long way into materials - weakly ionising = pass thro rather than collide with atoms. Stopped by very thick concrete or few cm of lead
What is alpha radiation used in?
Smoke detectors close to two electrodes as radiation ionises the air and current flows between electrodes when smoke = absorbs radiation so current stops and alarm sounds.
What is Beta used in?
Medical tracers swallowed and followed by external rad. detector = they know if body is working properly. Also thickness control amount of radiation goes down the paper is too thick
What is gamma used in?
High doses kill cells so can treat cancers directed at cancer so doesnt damge normal cells. Sterilise medical equipment by killing all microbes
What radiation is used in smoke detectors
Alpha radiation
What radiation is used for sterilising instruments
Gamma radiation
What radiation is used for medical tracers
Beta radiation
