Question

If a fossil originally had 200 g of C-14 how old would that fossil be if only 100 g remained?

A) 5,730 years
B) 2,865 years
C) 11,460 years
D) 8,595 years

Answer 1

The fossil would be approximately 5,730 years old because that is the half-life of carbon-14, and only half of the original C-14 remains in the sample.

Step-by-step explanation:

The process of determining the age of a fossil using the decay of carbon-14 (C-14) is known as radiocarbon dating. Given that the half-life of C-14 is 5,730 years, if a fossil originally had 200 grams of C-14, it would take one half-life, or 5,730 years, for the amount of C-14 to decay to 100 grams. Therefore, the fossil would be approximately 5,730 years old.

The half-life is the time required for half of the original concentration of an isotope to decay. Since half of the C-14 has decayed in this example, only one half-life has passed, making answer (A) 5,730 years the correct choice.