5. The half life of radioactive 32P is 14.3 days. How long does it take for 100 mg of this isotope to decay to 5 mg?

What is the half‑life of an isotope that decays to 3.125%3.125% of its original activity in 41.8 h?

How many hours are needed for a 16.0 g sample of Si-31 to decay to 2.0 g? The half-life for Si-31 is 2.6 h.

Radioactive vanadium-48 decays with a half-life of 16.0 days. a. What is the value of k in s? k = b. A sample contains 84.0 mg *°V. How many decay events will be produced in the first second? Assume the atomic mass of **V is 48.0 u. decays/s c. A chemist obtains a fresh sample of 48 V and measures its radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How long does she have to do the experiment? days

A radioactive sample has a decay constant of 1.32 x 10-3 h-1. What is its half life?

It takes 6400 years for one gram of a radioactive element to decay away to only 1/16 of a gram. The half-life of this element is

2. Tellurium-123 is a radioactive isotope occurring in natural tellurium. The decay constant is 1.7 x 1021 / s. What is the half-life in years?