Radioactivity and Particles
4 marks · EasyA sample of a radioactive material gives off radiation. A student is asked to describe this sample and measure its activity. The student is told to report results using standard units.
State the unit used to measure the activity of a radioactive sample.
Explain in one clear sentence what is meant by the activity of a radioactive sample.
Name one piece of equipment that can be used to detect ionising radiation from this sample.
Describe what happens to the activity of the sample over time.
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(a) becquerel (Bq)
(b) Activity is the number of radioactive decays per second.
(c) Geiger-Müller tube (or photographic film badge)
(d) The activity decreases over time.
Common mistakes: Giving incorrect unit, e.g., 'joule'; Describing 'activity' as 'energy' instead of 'number of decays per second'; Naming a device not used to detect radiation, like voltmeter; Saying activity increases with time
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct unit stated: becquerel (Bq)
B1 (b) · 1 mark · Correct definition of activity: number of decays per second stated.
B1 (c) · 1 mark · Correctly names GM tube or photographic film badge.
B1 (d) · 1 mark · Correct statement for decrease over time.
Worked solution
a) The unit of activity is the becquerel (Bq). b) Activity is the number of radioactive decays per second. c) A Geiger-Müller tube can be used to detect radiation. d) The activity decreases over time as the nuclei decay.