Final answer:
After two half-lives or 11 hours, only 25 mg of caffeine from an initial 100 mg in a cup of coffee will remain in the human body.
Step-by-step explanation:
The question involves calculating the amount of caffeine remaining in the body after 11 hours given that a cup of coffee contains about 100 mg of caffeine and the half-life of caffeine is approximately 5.5 hours. To find the amount remaining after two half-lives (11 hours), we apply the concept of half-life twice.
Calculation of Remaining Caffeine:
First Half-Life (5.5 hours): The amount of caffeine reduces to half of the initial amount, so 100 mg becomes 50 mg.Second Half-Life (additional 5.5 hours): The 50 mg further reduces to half, resulting in 25 mg remaining after 11 hours.
Therefore, after 11 hours, there would be 25 mg of caffeine left in the body from one cup of coffee.