1. The half-life of a radioactive nucleus is
(a) Half the time it takes for the entire substance to decay.
(b) The time it takes for half of the substance to decay.
(c) The same as the decay constant.
(d) Both (a) and (b) (they are the same).
(e) All of the above.
2. As a radioactive sample decays,
(a) The half-life increases.
(b) The half-life decreases.
(c) The activity remains the same.
(d) The number of radioactive nuclei increases.
(e) None of the above.