Units (Radioactivity)
2 marks · NormalDescribe how you would measure the activity of a radioactive source in the laboratory, naming all units used.
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Must show: mention of becquerel or Bq, seconds, Geiger counter or similar detector
Common mistakes: not stating units or methods
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Marking points
M1 · 1 mark · Describes using a detector (e.g., Geiger-Müller tube) and a timer or stopwatch to measure decays in a set time.
A1 · 1 mark · Correctly names units: activity in becquerels (Bq), time in seconds (s).
Worked solution
You would use a Geiger-Müller tube to count the number of decays from the source for a known time, measured with a stopwatch in seconds. The activity is calculated as the number of decays per second. The unit for activity is the becquerel (Bq) and for time is seconds (s).