Carbon-11 has a half-life of 20 minutes. Which of the following equations is used to calculate the amount of carbon-11 remaining after one hour if the starting material a 100-mg sample?
A) 100 mg* ½
B) 100 mg/3
C) 100 mg/20
D) 100 mg/20/20/20
E) 100 mg *½ * ½ * ½

Question

Quizplus · Accepted Answer

Carbon-11 has a half-life of 20 minutes, so in one hour (60 minutes), it will undergo three half-lives. The equation to calculate the remaining amount is to multiply the initial amount by (1/2) for each half-life: 100 mg * (1/2) * (1/2) * (1/2).

Carbon-11 Has a Half-Life of 20 Minutes