(Solved): The sketch graph shows the corrected count rate measured for the decay of a r ...

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The sketch graph shows the corrected count rate measured for the decay of a radioactive sample (the sample-detector distance is constant): (a) At time $$\mathrm{t}=0\mathrm{s}$$, what factors will affect the count-rate measured? (3) (b) If the count-rate is $$1200{\mathrm{s}}^{?1}$$ at $$\mathrm{t}=0\mathrm{s}$$, and is $$500{\mathrm{s}}^{?1}$$ after $$10\mathrm{s}$$, find the decay constant for the radioactive isotope. (2) (c) What is the half-life of this isotope? (1)