Radiation GCSE Flashcards
What is the radius of an atom?
1x10^-10m
List 3 causes of background radiation.
- Radon gas in the rocks
- Cosmic rays
3.Medical equipment
What precaution should one take to ensure an accurate result when measuring radiation?
Subtract the amount of background radiation from the total answer.
What is the term for exposure to radiation?
Irradiation.
What does irradiation mean?
Exposure to radiation, NOT make it radioactive.
What does contamination mean?
If an object has a radioactive substance introduced to it
What are methods of reducing irradiation?
Standing behind lead-lined boxes, Using remote controlled arms when working with radiation, simply being in a different room.
What is alpha radiation? State its charge and penetration.
Alpha radiation is high velocity alpha particles - helium nuclei. They have a charge of 2+ and low penetration.
What is beta- radiation? State its charge and penetration.
Beta- radiation is high velocity beta- particles (rogue electrons). That have a charge of 1- and medium penetration.
How does beta- decay occur?
A neutron splitting into a proton and electron, with the former remaining in the atoms nucleus and the electron being emitted as a beta- particle. Caused by unstable neutrons.
What is beta+ radiation? State its charge and penetration.
Beta+ radtiation is high velocity beta+ particles (rogue positrons) that have a charge of +1 and medium penetration.
How does beta+ decay occur?
An unstable proton splitting into a neutron and positron, with the former remaining in the atoms nucleus, and the positron being emitted as a beta+ particle. Caused by unstable protons.
What is gamma radiation? State its charge and penetration.
High energy EM waves released by an unstable nucleus, typically after a or b- decay, when the nucleus remains in an excited state with excess energy. It has no charge, but the highest penetration.
State 2 uses for alpha radiation.
- Smoke alarms
- Cancer treatment (radiotherapy)
State 3 uses for beta radiation
- Production of paper and aluminium foil. (-)
- Treatment of eye and bone cancer (-)
- PET Scanners (Positron Emission Tomography) (+)
State 2 uses for gamma radiation
- Sterilizing food and medical equipment
- External radiotherapy
What is neutron radiation? State its charge and penetration.
Emission of neutron particles. They do not have a charge. The penetration depends on the neutrons energy..
What is neutron emission used for?
Running nuclear fission in reactors.
What is the apparatus used to measure radiation?
Geiger-Muller Tube and Counter.
What is decay rate measured in and what does it signify?
Measured in becquerels (Bq), 1 Bq represents 1 decay per second.
What is half-life?
The amount of time it takes for the number of radioactive nuclei to halve.
How are substances with both short and long half-lives dangerous?
Short half-lives typically emit high radiation in a short amount of time and are highly dangerous, but quickly become safe. Long half-lives can emit radiation of millions of years and irradiate surrounding area.
What is nuclear fission?
The splitting of a large, unstable nucleus into smaller atoms. E.g Uranium into Krypton, Barium and 2 neutrons.
What triggers nuclear fission?
The absorption of a neutron by an unstable fissile nucleus, causing it to split.
Give 2 uses of nuclear fission.
-Nuclear reactors in power plants
-Nuclear weapons
How is fission sustained?
Nuclear fission causes the emission of more than 1 neutron. This means that the additional neutrons will be absorbed by other nuclei and trigger a chain reaction.
What is nuclear fusion?
The fusion of light elements such as hydrogen into helium, done by collision of high velocity hydrogen nuclei.
Why do the products of fusion not have the same mass as the reactants?
Some of the reactant mass is converted into energy as stated by E=mc^2.
