A researcher records the remaining number of nuclei N of a short-lived radon isotope at regular intervals. The data are shown below.
Time t (min) | Remaining nuclei N
0 | 1000
5 | 630
10 | 400
15 | 250
(1) Using any two successive data points, determine an experimental value for the half-life of this isotope. Show all steps in your calculation.
(2) From your half-life, compute the decay constant λ with proper units.
(3) Assuming the same decay rate continues, calculate the additional time after t=15min required for the number of nuclei to fall to 10 (i.e., 1% of the initial amount).