CAIE IGCSE Physics 5.2.4.2 Half Life From Data or Decay Curves Questions
Learn to correct detector readings for background radiation and identify half-life from successive count rates.
- Syllabus
- 2026–2028
- Course
- Physics 0625
Exam points
- subtract background count before testing whether a detector reading has halved
- find the interval between corrected readings that differ by one half-life
- add background count back when reporting the detector reading after decay
CAIE IGCSE Physics 5.2.4.2 Half Life From Data or Decay Curves Questions question 1
[Maximum number: 4]
Only one isotope of gold occurs naturally on Earth.
There are several artificially produced isotopes of gold.
Gold-198 ( 79198Au ) is an artificial isotope which is used in medicine and in scientific research.
Gold-198 decays by β (beta)-emission to a stable isotope of mercury.
Using Fig. 9.1, determine the half-life of gold-198.
half-life =
2.4 days ≤ τ ≤ 2.9 days
count rate from line – background count e.g. 390 – 20
answer from first C1 mark divided by 2 e.g. 370/2 or 185
background count + answer from second C1 mark e.g. 20 + 370/2 or 20 + 185 or 205
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