Radioactive Decay

Question

Strontium-90 is a radioactive isotope that decays exponentially at a rate of 2.8% per year. The amount of strontium-90, S, remaining after t years can be determined by the function S1t2 = S0e-0.028t, where S0 is the original amount present. If there are originally 1000 grams of strontium-90, determine the amount of strontium-90 remaining after 40 years. Round your answer to the nearest gram.

Answer 1

S(t) = S₀ e^-0.028t

S₀ = 1000 g

S(t) = (1000 g) e^-0.028t

You have a complete equation for S(t), with t in years. Just plug t=40 into S(t) and evaluate.