Question

The half-life of uranium-235 is 700 million years. If you start with 50 atoms of it, how many will you have left after 700 million years?

A. 50
B. 100
C. 25
D. 45

Answer 1

After 700 million years, the number of atoms left is 25, the correct option is C.

How many will you have left after 700 million years?

We define the half-life as the time in which a given quantity of a radioactive element decays to half of that quantity.

Here we know that the half-life of Uranium-235 is 700 million years.

So, if we have a quantity A of Uranium-235, after 700 million years, we will have A/2 of Uranium-235

In this case we start with 50 atoms, then after 700 million years we will have 50/2 = 25 atoms.

Then the correct option is C.

If you want to learn more about half-life.

https://brainly.com/question/11152793

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