Radioactivity Flashcards
(28 cards)
What are the 3 different types of ionising radiation?
Alpha
Beta
Gamma
What are the properties of alpha radiation?
-contains 2 protons and 2 neutrons
-it is the largest
-it is the slowest
-its charge is +2e
-it is absorbed by paper,skin,a few cm of air
-harmful inside body
What are the properties of beta radiation?
-contains a single electron
-small
-close to speed of light
-change= -1e
-absorbed by light metals, a few mm of aluminium and a few m of air
-can harm inside body and can pass into body from outside the skin
What are the properties of gamma radiation?
-no size
-fastest (speed of light)
-no charge
-absorbed by a thick sheet of lead, meters of concrete and 1000s of kms of air
-harmful both inside and outside of body
What do geiger counters do?
They detect radioactivity and turn it into a current which can be displayed as a value or a sound (click).
What is the activity of a radioactive source?
The number of radioactive nuclei decaying per second
What is activity measured in?
Becquerels (Bq)
Radioactive decay decreases exponentially. Explain.
-it decreases rapidly at first and then slows down as there are fewer stable nuclei left to decay
-the sources decays at a fixed rate which can be measured by using its ‘half life’
What is half life?
The time taken for activity of a radioactive source to fall by half
What is carbon 14?
It is an isotope of carbon that is radioactive. It decays through beta decay to form nitrogen.
What is contamination?
The source is inside your body or on your skin or clothing
What is iradiation?
You are exposed to radiation from and external source outside your body and clothes
What is ionising radiation?
Radiation with enough energy to change the electron structure of an atom
How can radiation affect a person?
-radiation enters body
-radiation ionised atoms in cells DNA
-these mutations could become cancerous cells
safety precautions to take when using radioactive sources:
-reduce your time of exposure
-handle with tools or tongs
-wear protective clothing
-point source away from body
-contain sources behind thick lead
-when Finnished, use a geiger counter to see how much radiation you have been exposed to
Uses of alpha radiation?
Smoke alarms
Powering small devices
Fuel sources for satellites
Old pacemakers
Uses of beta radiation
-testing thickness of thin sheet material
-medical tracers to look inside the body
-particle physics
Uses for gamma radiation
-sterilising medical equipment
-sterilising food
-radiotherapy
What are the advantages of nuclear power?
-very efficient
-does not produce greenhouse gases
-very reliable
-not much waste produced
-uranium about the same price as coal
Disadvantages of nuclear power?
-waste is radioactive and potentially dangerous for a very long time and difficult to store
-power station accidents can be catastrophic
-power stations are expensive to build and decommission due to safety measures
What is nuclear fission?
It is the splitting of an atom which releases energy. It can be spontaneous but in a nuclear reactor it is made to happen.
How does nuclear fission happen?
Nuclear fission is the chain reaction when massive, neutron rich Nuclei are split when a slow moving neutron collides with them. This splitting causes vast amounts of energy, the nucleus splits into two daughter nuclei as well as releasing more neutrons to create a self sustaining chain reaction.
What is a common nuclear fuel and why?
Uranium because it’s nucleus is very large and unstable
Nuclear fusion is the opposite of nuclear fission. True or false
True
