A large collection of nuclei are undergoing alpha decay.The rate of decay at any instant is proportional to:
A)the number of undecayed nuclei present at that instant
B)the time since the decays started
C)the time remaining before all have decayed
D)the half-life of the decay
E)the average time between decays

Question

Quizplus · Accepted Answer

The rate of decay, or activity, of a radioactive substance is proportional to the number of undecayed nuclei present at that instant, as described by the law of radioactive decay.

A Large Collection of Nuclei Are Undergoing Alpha Decay