Radiation and Risk Flashcards
Describe the structure of an atom
A nucleus of protons and neutrons surrounded by electron shells
What is a positive ion?
An atom which has lost one or more electrons
What is a negative ion?
An atom which has gained one or more electrons
State the three forms of radiation
Alpha, beta, gamma
Which form of radiation is the most penetrating?
Gamma (then beta, then alpha)
Which form of radiation has the furthest range?
Gamma (then beta, then alpha)
Which form of radiation is the most ionising?
Alpha (then beta, then gamma)
Which form of radiation is stopped by paper?
Alpha
Which form of radiation is stopped by aluminium foil?
Beta
Which form of radiation is reduced by thick lead?
Gamma
What is alpha radiation?
Two protons and two neutrons (a helium nucleus)
What is beta radiation?
Electron
What is gamma radiation?
Electromagnetic wave
State the use of alpha radiation
Smoke alarms
State the use of beta radiation
Controlling the thickness of sheet materials like paper
State the uses of gamma radiation
Treating cancer, sterilising medical equipment and food
How does alpha radiation affect an atom’s atomic mass?
Decreases it by 4
How does alpha radiation affect an atom’s proton number?
Decreases it by 2
How does beta radiation affect an atom’s mass?
Stays the same
How does beta radiation affect an atom’s proton number?
Increases by 1
Why does beta radiation increase an atom’s proton number?
A neutron decays to become a proton and an electron. The electron is emitted as radiation and the extra proton increases the proton number by one
How does gamma radiation affect an atom’s mass?
Stays the same
How does gamma radiation affect an atom’s proton number?
Stays the same
Why doesn’t gamma radiation affect the mass or proton number of an atom?
It is a wave so has no mass
Define half-life
The time taken for the number of raidoactive isotopes in a sample to halve
Why do we use half-life to predict when a radioactive sample will become safe?
Nuclear decay is random, half-life gives us an estimate and we know that a radioactive sample will become safer after multiple half-lives
State the units for nuclear decay
Becquerels (Bq)
Define irradiation
When an object is exposed to radiation but does not become radioactive itself
Define contamination
When radioactive material is transferred onto another object or organism and continues to emit radiation
How can we prevent irradiation?
Store in a lead-lined box, use robotic arms when handling
How can we prevent contamination?
Use tongs, wear gloves and protective suits when handling
What do Sieverts (Sv) measure?
The dose of radiation
Which type of radiation is more dangerous inside the body?
Alpha
Which type of radiation is more dangerous outside the body?
Gamma
State three sources of background radiation
Cosmic rays, rocks and soil, fallout from nuclear testing, living organisms
What is a tumour?
Uncontrolled cell growth and division resulting in a lump
What is a benign tumour?
A tumour which is not cancerous and stays in the same place, usually stops growing and is harmless unless its growth affects vital organs
What is a malignant tumour?
A tumour which is cancerous and spreads around the body via blood
What causes cancer?
Ionising radiation causes atoms in DNA to become ions, this damages DNA and causes mutations in cells, cells start to grow and divide uncontrollable to form a malignant tumour
State two treatments for cancer
Chemotherapy (drugs) and radiotherapy (exposure to gamma radiation)
Give three risk factors for cancer
Smoking, exposure to radiation, alcohol, family history/genetics
What is a radioactive half life?
Time taken for half the radioactive nuclei to decay
What stops alpha radiation?
Paper, skin
What stops beta radiation?
Aluminium
What stops gamma radiation?
Concrete, lead
