Phosphorus-32 is radioactive and has a half life of 14.3 days. Calculate the activity of a 9.1 mg sample of phosphorus-32. Give your answer in becquerels and in curies. Round your answer to 2 significant digits. Bq Oci §

A sample of rock was found to contain 8.23 mg of rubidium-87 and 0.47 mg of strontium-87.. (a) Calculate the age of the rock if the half-life of the decay of rubidium by emission is 4.71010 y. (b) If some S3887r was initially present in the rock, would the rock be younger, older, or the same age as the age calculated in (a)? Explain your answer.