Question

6. The half life for uranium-235 is 7.0x108 years.

a. How many half-lives did the sample go through at the end of 2.8x10 years​

Answer 1

`\large \boxed{4.0}`

Step-by-step explanation:

`\text{No. of half-lives} = 2.8  * 10^(9 ) \text{ yr} * \frac{\text{1 half-life}}{7.0 * 10^(8) \text{ yr}} = \textbf{4.0 half-lives}\\\\\text{The sample went through $\large \boxed{\textbf{4.0 half-lives}}$}`