The phosphorous-?32 isotope has a half-life of 14.3 days. a) What is the decay constant for P-32 expressed in units of sec? b) What is the activity of a 1.00 mg sample of P-32? c) Approximately what mass of 32P will remain in the original 1.00 mg sample after 57 days? d) What is the rate of radioactive decay after 57 days?