Radioactivity and Particles Flashcards
(22 cards)
Describe the nature of Alpha particles?
1) Helium nuclei
2) Low penetrating power
3) Highly ionising
4) Emitting an alpha particle decreases the atomic number of the nucleus by 2
Describe the nature of beta particles?
1) Is an electron
2) Moderate penetrating power
3) Moderately ionising
Describe the nature of gamma rays?
1) Doesn’t have a mass
2) High penetrating power
3) Low ionising power
What machine can detect radiation sources?
Geiger-Muller detector
What are some sources of background radiation?
Stars, bananas, smoke detectors
What is the definition of half life and what is it measured in?
Time taken for half of the radioactive atoms to decay, Becquerels
What are some uses of radiation in medicine?
X-rays, treat cancer through chemo
What is irradiation?
When something is exposed to radiation
What is contamination?
When radiation gets onto an object that is unwanted
What stops alpha particles?
Paper
What stops beta particles?
Aluminium
What stops gamma rays?
Thick lead or thick concrete
What are the dangers of radiation?
Cause mutations
Damage cells and tissue
Harm the environment when being disposed(if not done properly)
What do nuclear power stations use?
Fission chain reactions
What is nuclear fission?
Splitting of an atom which releases energy. It often uses uranium-235. When uranium-235 is split it produces two new daughter nuclei which are radioactive. This releases lots of kinetic energy stores
How are nuclear reactors kept safe.
Shielding
Control rods
Moderators
What does shielding do?
Absorb the ionising radiation
What do control rods do?
Made of boron and limit the rate of fission by absorbing excess neutrons
What do moderators do?
Usually graphite or water, slows the neutrons down
How does nuclear fusion work?
Two nuclei collide at high speeds to fuse creating a larger nuclei. The new nuclei has les mass as the rest of the mass is converted into lots of energy
Why is nuclear fusion hard to do?
It requires high temperature and high pressures which make it useless as it would use more energy than released
Where is nuclear fusion found naturally?
In stars
