Half-life (AQA GCSE Physics Combined Science): Flashcards
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Definition of half-life
Definition of half-life
Time for half the unstable atoms in a radioactive sample to decay
What does activity of a radioactive source measure?
What does activity of a radioactive source measure?
How many atoms are decaying each second
Unit for measuring activity
Unit for measuring activity
Becquerels (Bq)
Can we predict when one specific atom will decay?
Can we predict when one specific atom will decay?
No, but we can predict the overall pattern for many atoms
% of original atoms remaining after 1 half-life
% of original atoms remaining after 1 half-life
50%
% of original atoms remaining after 2 half-lives
% of original atoms remaining after 2 half-lives
25%
% of original atoms remaining after 3 half-lives
% of original atoms remaining after 3 half-lives
12.5%
Name of the decay curve shape on a graph
Name of the decay curve shape on a graph
Exponential decay curve
What does the y-axis show on a radioactive decay graph?
What does the y-axis show on a radioactive decay graph?
Activity (in Bq)
What does the x-axis show on a radioactive decay graph?
What does the x-axis show on a radioactive decay graph?
Time
Why does the decay curve get less steep over time?
Why does the decay curve get less steep over time?
Fewer atoms left to decay
Does each radioactive isotope have the same half-life?
Does each radioactive isotope have the same half-life?
No, each isotope has its own unique half-life