Problema Solution

The radioactive element has a half-life of 432 years. start with 20-g mass. how much will be left after 367 years?

Answer provided by our tutors

The amount A of the radioactive material present at a time t is given by the model


A = A0*(1/2)^(t/h)


where A0 is the amount present initially, h is the half-life of the material.


In our case we have


A0 = 20 g


h = 432 years half-life


t = 367 years


A = 20*(1/2)^(367/432)


by solving we find


A = 11.1 g


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there will be 11.1 grams left after 367 years.