The "half-life" of a large collection of radioactive nuclei is
A) the number of nuclei that decay in 1 second.
B) the number of nuclei that remain after 1 second.
C) larger for heavy nuclei than for lighter nuclei.
D) the time for half of the collection to decay.

Question

Quizplus · Accepted Answer

The half-life of a large collection of radioactive nuclei is the time for half of the collection to decay. Therefore, option D is the correct answer. Option A is incorrect because it refers to the decay rate, which is not the same as half-life. Option B is incorrect because it only describes the number of nuclei remaining after a certain time, not the half-life. Option C is also incorrect because the half-life does not depend on the mass of the nucleus.

The "Half-Life" of a Large Collection of Radioactive Nuclei Is