Question

Element X is a radioactive isotope such that every 26 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 390 grams, how long would it be until the mass of the sample reached 260 grams, to the nearest tenth of a year?​

Answer 1

It will take 15.029 years for element X to reach mass of 260 grams

Explanation:

The half life period of radioactive element X is 26 years

The initial mass of radioactive element X is 260 grams

Elapsed time = half life * log (beginning amount /ending amount)/log 2

Substituting the given values, we get

Elapsed time = 26 * log (390/260)/log 2

= 15.209 years