In the semi-log plot of log10A (ordinate) versus time (abscissa) for a radioactive sample, the straight line falls from 3.60 to 2.40 in 50 h.
(i) Calculate the numerical value of the slope of the line.
(ii) Hence determine the decay constant λ (in h−1) and the half-life of the isotope.
(iii) If the sample initially contains 1.5 mg of the isotope (pure, atomic mass = 60 u), estimate the mass that will remain after 200 h.