When dealing with radioactive decay of materials, we often read about the age of a particular rock. What is meant by the age of a rock?
A)It is the age of the atoms within the rock.
B)It is the time since the rock was formed and the elements within the rock were isolated with definite abundance ratios.
C)It is the age of the planet or moon on which the rock is found.
D)It is actually a misnomer, since only radiogenic elements can be dated. A rock can be dated only if it is a pure radiogenic element.

Question

Quizplus · Accepted Answer

The age of a rock refers to the time elapsed since it was formed and since the elements within the rock were isolated with definite abundance ratios. This is determined through the measurement of the abundance of certain radiogenic isotopes (such as uranium-238 and potassium-40) and their decay products in the rock. Therefore, option B is the most accurate choice. Option A is partially correct, as the age of a rock is related to the age of the atoms within it, but this is not the complete picture. Option C is incorrect, as the age of a rock is not necessarily related to the age of the planet or moon on which it is found. Option D is also incorrect, as any rock can potentially be dated through radiometric methods, although the accuracy of the dating may vary depending on the type of rock and the isotopes used.

When Dealing with Radioactive Decay of Materials, We Often Read