Radioactive decay: A radioactive isotope decays by β^- emission with a half-life of 1.0 min. During the first 1.0 min, a particular sample emits 1000 β^- particles. During the next 1.0 min, the number of β^- particles this sample will emit will be closest to

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Since the half-life is 1.0 min, this means that for every 1.0 min, the amount of radioactive decay will decrease by a factor of 2. In the first 1.0 min, the sample emits 1000 particles, so we know that it had twice that amount (2000 particles) 1.0 min before. Therefore, after 2.0 min, the sample would have emitted a total of 2000 + 1000 = 3000 particles. However, since the amount of radioactive decay decreases by a factor of 2 every 1.0 min, we know that only half of those particles (1500) will be emitted in the second 1.0 min. Therefore, the answer is closest to 500 particles (choice B).

Radioactive Decay: a Radioactive Isotope Decays by β- Emission with a Half-Life

Radioactive Decay: a Radioactive Isotope Decays by β^- Emission with a Half-Life