Answer to Question #126762 in General Chemistry for Allisan

Question

A radioactive isotope has a half life of 42.8 minutes. How long will it take for the radiation from a 580 pCi sample to decrease to 36 pCi?

Answer 1

Half-life of the isotope = 42.8 minutes

Original population = 580pCi

Final population = 36pCi

lets calculate the number of half-lifes for decay of the isotope:

580...290...145...72.5...36.25

Hence, we have 4 half-lifes to work with

and each half-life taken 42.8 minutes

Then the duration taken for the decay = 4*42.8 = 171.2 minutes