An animal skeleton has a carbon-14 decay rate of 13.1 disintegrations per minute per gram of carbon. When did the animal die? (Assume that living organisms have a carbon-14 decay rate of 15.3 disintegrations per minute per gram and that carbon-14 has a half-life of 5730yrs.)

1034 yrs

Explanation:

The equation to use in this question is:

t = - 2.303/k log (A/A₀) where

A = present number of disintegrations

A₀ = intial number of disintegrations

k = decay constant

The decay constant we will obtain it from the given hal-life:

k: 0.693/t₁/₂, t₁/₂ = half-life ⇒

k: 0.693 / 5730 y = 1.209 x 10⁻⁴ / y⁻¹

t = - 2.303 / 1.209 x 10⁻⁴ / y⁻¹ x log (13.1/15.3) = 1034 yrs