If a 3.16-g sample of an isotope having a mass number of 135 decays at a rate of 0.530 Ci, what is its half-life?

The half-life for the decay of carbon-14 is 5.73*10^3 years. Suppose the activity due to the radioactive decay of the carbon-14 in a tiny sample of an artifact made of wood from an archeological dig is measured to be 6.1*10^3 Bq. The activity in a similar-sized sample of fresh wood is measured to be 6.9*10^3 Bq. Calculate the age of the artifact. Round your answer to 2 significant digits.

In a piece of rock from the Moon, the 8/Rb content is assayed to be 1.89×1010 atoms per gram of material and the 8/Sr content is found to be 1.08x109 atoms per gram. (The relevant decay is 87Rb → 87Sr + e¯. The half-life of the decay is 4.8 x 10 yr.) 10 (a) Determine the age of the rock. yr (b) Could the material in the rock actually be much older? No, it could not be any older. Yes, it could be much older. (c) What assumption is implicit in using the radioactive-dating method? We assume that none of the 8/Sr nuclei came from the decay of 8/Rb nuclei. We assume that all of the 8'Sr nuclei came from the decay of 8'Rb nuclei. We assume that some of the 8Sr nuclei came from the decay of 87 Rb nuclei while the rest was present initially.

The common isotope of uranium, 238U, has a half-life of 4.47 * 109 years, decaying to 234Th by alpha emission. (a) What is the decay constant? (b) What mass of uranium is required for an activity of 1.00 curie? (c) How many alpha particles are emitted per second by 10.0 g of uranium?