Radioactive decay (AQA GCSE Physics Combined Science): Flashcards
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Is radioactive decay predictable?
Is radioactive decay predictable?
No - it's random and unpredictable for individual nuclei
What happens to unstable atomic nuclei over time?
What happens to unstable atomic nuclei over time?
They break down and release radiation (radioactive decay)
Composition of an alpha particle
Composition of an alpha particle
Helium nucleus: 2 protons and 2 neutrons
Charge of an alpha particle
Charge of an alpha particle
+2 (positive)
Alpha particle ionising power
Alpha particle ionising power
Very strong
What stops alpha particles?
What stops alpha particles?
Thin sheet of paper or 5cm of air
What is a beta particle?
What is a beta particle?
High-speed electron ejected from nucleus
Charge of a beta particle
Charge of a beta particle
-1 (negative)
What stops beta particles?
What stops beta particles?
Few millimetres of aluminium
What are gamma rays?
What are gamma rays?
High-energy electromagnetic waves
Charge and mass of gamma rays
Charge and mass of gamma rays
Both 0 (neutral, no mass)
What stops gamma rays?
What stops gamma rays?
Thick lead or several metres of concrete
Charge of neutrons
Charge of neutrons
0 (neutral)
Relationship between ionising & penetrating power
Relationship between ionising & penetrating power
Inverse: high ionising = low penetrating, vice versa
When are alpha particles most dangerous?
When are alpha particles most dangerous?
If swallowed or breathed in (inside body)