IB Physics SL E.3.11 Activity, Count Rate & Half-Life
Practise extracting half-life from graphs or tables and separating source activity from background count rate.
- Syllabus
- First assessment 2025
- Objective
- —
- Level
- SL
Exam points
- subtract background count before using successive halving to estimate half-life
- apply repeated half-lives or exponential decay to predict later activity or count rate
- test whether data follow radioactive decay by checking for a constant half-life
E.3.11—Activity, count rate and half-life question 1
This section consists of three questions: B1, B2 and B3.
Question (a)
(a)
The isotope tritium (hydrogen-3) has a radioactive half-life of 12 days.
[ 1 ]
Question (i)
(i)
Define radioactive half-life.
[ 1 ]
Question (b)
(b)
A sample of tritium has an activity of at time t=0. The half-life of tritium is 12 days.
[ 2 ]
Question (i)
(i)
Using the axes below, construct a graph to show how the activity of the sample varies with time from t=0 to t=48 days.
[ 2 ]
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