The decay rate of an alpha emitter sample is 975 disintegrations/minute. Exactly 1 hour later the sample decays at a rate of 644 disintegrations/minute. What is the half-life of this alpha emitter?

Question

Quizplus · Accepted Answer

The half-life of an alpha emitter is the time it takes for half of the radioactive atoms in a sample to decay. The decay rate of an alpha emitter is proportional to the number of radioactive atoms in the sample. Therefore, the half-life of an alpha emitter can be calculated by dividing the initial decay rate by the final decay rate and then taking the natural logarithm of the result. In this case, the initial decay rate is 975 disintegrations/minute and the final decay rate is 644 disintegrations/minute. Therefore, the half-life of this alpha emitter is:t1/2 = ln(975/644) / (975 - 644) = 100 min

The Decay Rate of an Alpha Emitter Sample Is 975