Tritium (
H )is an isotope of hydrogen that is sometimes used to make the hands of watches glow in the dark.The half-life of tritium is 12.3 years.After 49 years,approximately how much of the original tritium remains?

Question

Tritium ( 
H )is an isotope of hydrogen that is sometimes used to make the hands of watches glow in the dark.The half-life of tritium is 12.3 years.After 49 years,approximately how much of the original tritium remains?

Quizplus · Accepted Answer

Since the half-life of tritium is 12.3 years, after 4 half-lives (49/12.3), the amount of remaining tritium will be 1/2^4 or 1/16 of the original amount. 
So, approximately 6.25% of the original tritium remains. 
Therefore, the correct choice is D) 6.25%.

Tritium ( H )Is an Isotope of Hydrogen That Is Sometimes Used