(a(i))[3]
Calculate the half-life of the substance.
(a(ii))[2]
Calculate the detected count rate at time = 9.6 minutes.
(b)[3]
State and explain if the student’s suggestion is correct.
Physics 0625 · IGCSE · Radioactivity
Radioactivity — practice question
A student is examining a radioactive sample in a laboratory. Fig. 11.1 presents a graph of the detected count rate as the sample decays over 7.5 minutes. The axes are marked count rate in counts/min and time in minutes. Background radiation is 20 counts/min.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “initial count rate corrected for background = 220 - 20 = 200” …
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