Question

Uranium-238 has a half-life of 4.5 billion years. If Earth is about 4.5 billion years old, which statement is true? A. In about 4.5 billion years, there will be the same amount of uranium-238 as there is today. B. About 4.5 billion years ago, there was half as much uranium-238 as there is today. C. About 4.5 billion years ago, there was twice as much uranium-238 as there is today. hellppppppp mmeeeeeeeee

Answer 1

Answer: C. About 4.5 billion years ago, there was twice as much uranium-238 as there is today.

Step-by-step explanation: Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations.

Half life of a radioactive material is the time taken by the material to decompose to half of its original value.

Thus if Uranium-238 has a half-life of 4.5 billion years, it means it has decomposed to half of its original value and thus about 4.5 billion years ago, there was twice as much uranium-238 as there is today.

In next 4.5 billion years, i.e. after two half lives have passed, the amount of uranium will be one fourth of ts original value.