Half-life is defined as the amount of time, often in years, that it takes for a radioactive substance to lose half its radioactivity.

Question

Half-life is defined as the amount of time, often in years, that it takes for a radioactive substance to lose half of its radioactivity. If a substance has a half-life of 58 years and starts with 500 grams radioactive, then how much remains radioactive after 30 years? Round to the nearest gram.

Answer 1

Let A = amount left.

Let A₀ = starting amount = 500g

T = time gone by = 30 years

h = half-life = 58 years

The equation for calculating the amount left is A = A₀(1/2)^T/h

A = (500)(1/2)^30/58