Physics

Problem

Carbon-14 dating is rarely useful for specimens older than about

5\times10^{4}\,

years. Which of the following best explains this limitation? a) Cosmic rays completely stop producing

^{14}\text C

after

5\times10^{4}\,

years have elapsed. b) After such a long time the remaining

^{14}\text C

activity becomes too low to measure accurately. c) The

\beta

particles from

^{14}\text C

decay are fully absorbed by the specimen after about

5\times10^{4}

years, so detectors cannot register them. d) The half-life of

^{14}\text C

increases with the age of the sample, giving unreliable results.