Strontium 90 is a radioactive material that decays according to the function upper a (t )equals upper a 0 e superscript negative 0.0244 t baseline comma where upper a 0 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 600 grams of strontium 90 be left? (d) what is the half-life of strontium 90?

a) λ = 0.0244 y⁻¹

b) 627 g

c) 11.8 years

d) 28.4 years

Explanation:

Strontium 90 is a radioactive material that decays according to the function

where,

A(t) is the amount present at time t (in years)

A₀ is the initial amount present

0.0244 is the decay rate λ

Assume that a scientist has a sample of 800 grams of strontium 90. (a) What is the decay rate of strontium 90?

(a) What is the decay rate of strontium 90?

According to the exponential decay function, the decay rate is λ = 0.0244 years⁻¹

(b) How much strontium 90 is left after 10 years?

If A₀ is 800 g and t is 10 years, A(t) is:

(c) When will only 600 grams of strontium 90 be left?

If A₀ is 800 g and A(t) is 600 g, t is:

(d) What is the half-life of strontium 90?

We can calculate half-life using the following expression.