Question

The half-life of radium-226 is 1590 years. If a sample contains 400 mg how many mg will remain after 4000 years?

Answer 1

69.9 mg

Explanation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is time,

and T is the half life.

A = 400 (½)^(4000 / 1590)

A = 69.9 mg