Section 7 Radioactivity Flashcards
(18 cards)
What are the characteristics of an alpha particle?
Like a helium atom, Atomic number 2, Mass number 4
What are the characteristics of a beta particle?
Negatively charged (−1), A neutron splits into a proton and electron, The electron is the beta particle
What are the characteristics of gamma radiation?
No charge, No mass, No atomic number
What does ionising mean?
Damaging
What does the radioactivity of a sample depend on?
Number of unstable nuclei, Average half-life of the nuclei
What is the unit of radioactivity?
Becquerel (Bq)
What is neutron radiation?
When an unstable nucleus emits a neutron to reduce mass number
What is radioactive decay?
The process where an unstable atomic nucleus spontaneously emits radiation and changes into a different nucleus, often of a different element.
Emission can be alpha, beta, gamma or neutron
What is radioactive half-life?
Time taken for half of the unstable nuclei in a sample to decay
What is nuclear fission?
Splitting of a heavy radioactive nucleus, Produces two daughter nuclei and releases energy as gamma rays
What is nuclear fusion?
When two small nuclei collide and fuse, Produces a larger nucleus and releases gamma rays
What types of radiation can penetrate the body and damage internal organs?
Beta radiation, Gamma radiation
What is the difference between irradiation and contamination?
Irradiation = exposure to radiation, Contamination = radioactive particles get onto or into an object
Why is alpha radiation dangerous inside the body but not outside?
It can’t penetrate skin, But causes severe damage if ingested/inhaled
How is radiation used in medicine?
Medical tracers (beta or gamma), Radiotherapy to kill cancer cells
Why are gamma rays used to sterilise food and equipment?
Kill microbes, No high temperature needed, Don’t damage materials
How is beta radiation used in industry?
Used in thickness gauges to monitor material thickness (e.g. paper or foil)
Why is radioactive waste difficult to dispose of?
High-level waste stays radioactive for thousands of years, Must be stored securely to prevent leaks
