Strontium 90 is a radioactive material that decays according

Strontium 90 is a radioactive material that decays according to the function A(t) = A0 e-0.0244t, where A0 is the initial amount present and A is the amount present at time t (in years). Assume that a scientist has a sample of 800 grams of strontium 90. (a) What is the decay rate of strontium 90? (b) How much strontium 90 is left after 10 years? (c) When will only 200 grams of strontium 90 be left? (d) What is the half-life of strontium 90? (a) What is the decay rate of strontium 90?

Solution

a)   k=decay rate = 0.0244 year^-1

b) A(t) =800g*e^-0.244=626.79g

c) 200g =800g*e^-0.0244t -> t= 56.815 years

d) 1/2 = *e^-0.0244t - >t = 28.407 years