The half-life of carbon-14 is about 5370 years. What percent of the original carbon-14 would you expect to find in a sample after 2500 years?

If t is the half life of a radioactive substance the percentage (p) of the radioactive material left after time T is given by:

p = 100*[0.5^(T/t)]

It is given:

Half life of carbon-14 = t = 5370 years, and

Actual time elapsed = T = 2500 years

Substituting these values in equation for p we get:

p = 100*[0.5^(2500/5370)] = 72.4195

Answer:

72.4195 percent of carbon-14 will remain after 2500 years