Question

The half-life of Carbon-14 is 20 years. What is the mass of the original sample if 10g of Carbon-14 is left after 40 years?

A) 20g
B) 40g
C) 80g
D) 160g

Answer 1

The mass of the original sample is 20g.

Step-by-step explanation:

To find the mass of the original sample, we can use the concept of half-life. The half-life of Carbon-14 is 20 years, which means that after 20 years, half of the original sample will remain. After another 20 years (a total of 40 years), only one-fourth (25%) of the original amount will remain.

If 10g of Carbon-14 is left after 40 years, then the original sample must have been twice that amount, which is 20g. So, the correct answer is A) 20g.