Question

The initial amount of radioactive substance is 52 grams. The substance decays at a rate of 1%. After 12 years, how many grams of the substance is present? Approximate to the nearest gram.

Answer 1

If the rate of decay is 1% per year, the number of grams present after 12 years is found from:

`52*(0.99)^(12)=46\ grams`
An alternative solution can use the following equation:

`N(t)= N_(0) e^(-\lambda t)`
Plugging in given values, we get:

`N=52* e^(-0.01* t)=46\ grams`