Physics

Problem

In a laboratory experiment, the activity of a pure radioactive sample fell from

6.4\times10^{4}\,\text{Bq}

2.5\times10^{4}\,\text{Bq}

90\,\text{minutes}

. a. (i) Derive an expression for the half-life of a radionuclide in terms of two measured activities

A_1

(at time

t_1

) and

A_2

(at time

t_2

), where

t_2>t_1

. b. (ii) Using your derived expression, determine the half-life of the sample in minutes. c. (iii) Calculate the additional time required for the activity to fall to

5.0\times10^{3}\,\text{Bq}

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