Determine the half-life of a sample of robindium that decays to 25% of its original amount after 2.4 hours

Question

Determine the half-life of a sample of robindium that decays to 25% of its orginal amount after 2.4 hours

Answer 1

25% is 1/4 = (1/2)²

 

So it will have decayed to 25% in exactly 2 half-lives, which is given as 2.4 hours.

 

So one half-life is 1.2 hours.