Question

Which pair of elements can be used to determine the age of a fossil that is over one billion years old?

Answer 1

Answer: Option (4)

Explanation: The most efficient radioactive method used for the determination of fossil age which is about one billion years old is the Potassium-Argon method (⁴⁰K-⁴⁰Ar).

Potassium-Argon method is generally used to date fossils which are more than 1.2 billion years old as its half life is almost about 1.2 billion years. Potassium is highly radioactive, which converts into Argon and becomes stable.

Uranium and Carbon are also highly radioactive whereas Lead and Nitrogen are stable elements.

¹⁴C-¹⁴N is not an efficient method as it has a half life of only about 5700 years.

Thus the correct answer is option (4).

Answer 2

Answer:

Explanation:

There are some radioactive nuclides can be used to measure time on an archeological scale. One is the best example of this is radiocarbon dating. This process is based on the ratio of caebon-14 to carbon-12 in the atmosphere which is relatively constant.

The half time of C-14 5730 years  

Carbon-14 is a radioactive nucleus. It has a half-life of 5730 years.

All living tissues like plants and animal absorbed carbon-12 along with carbon-14 with same ratio of caebon-14 to carbon-12 in the atmosphere.

Carbon-14 dating is based on the ratio of carbon-14 to carbon-12 in the atmosphere which is relatively constant

Answer 3

It is D, or the last one, or potassium, which is radioactive, and argon, which is stable. lol!