The table below lists the measured count rate of a radioactive sample over a period of 18 hours.
Elapsed time t / hoursCount rate / counts/s01200384966009424123001521218150 \begin{array}{|c|c|} \hline \text{Elapsed time } t \text{ / hours} & \text{Count rate / counts/s} \\ \hline 0 & 1200 \\ 3 & 849 \\ 6 & 600 \\ 9 & 424 \\ 12 & 300 \\ 15 & 212 \\ 18 & 150 \\ \hline \end{array} Elapsed time t / hours0369121518Count rate / counts/s1200849600424300212150Which of the three common types of radioactive emission (α\alphaα, β\betaβ, or γ\gammaγ) has neither mass nor charge? State the region of the atom from which all three emissions originate.
Using the data provided in the table: Determine the half-life of this radioactive substance.
Using the data provided in the table: Calculate the time taken for the count rate of this sample to decrease from 800 counts/s800\text{ counts/s}800 counts/s to 200 counts/s200\text{ counts/s}200 counts/s.
A different sample of the same radioactive substance has an initial count rate of 3200 counts/s3200\text{ counts/s}3200 counts/s. Calculate the time required for its count rate to decrease to 400 counts/s400\text{ counts/s}400 counts/s.
484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.