Question

The amount of a radioactive substance remaining after t years is given by the function , where m is the initial mass and h is the half-life in years. Cobalt-60 has a half-life of about 5.3 years. Which equation gives the mass of a 50 mg Cobalt-60 sample remaining after 10 years, and approximately how many milligrams remain?

Answer 1

Equation: m(t) = 50*(1/2)^(t/5.3) mg.

After 10 years: m(10) = 50*(1/2)^(10/5.3) ≈ 50*(0.2707) ≈ 13.5 mg (about 13.53 mg).