physics

Question

 A 28 gram sample of a radioactive isotope undergoes radioactive decay. If the half life of the

isotope is 45 minutes, how much of this isotope remains after 6.0 hours?

Answer 1

Use the formula : .

From the given data : Initial amount = 28 grams,

                                 Half life () = 45 minutes = 45 * 60 = 2700 seconds, and

                                 After remains the time = t = 6.0 hours = 6.0 * 60 * 60 = 21600 seconds.

Substitute the values : initial amount = 28 grams, t = 21600 seconds, and = 2700 seconds.

.

Therefore, 0.1095 grams of the isotope remains after 6.0 hours.