Question

If the half-life of a radioactive substances is 590 million years and you have 40 atoms of it, how many half-lives will have passed when 5 atoms remain

Answer 1

3

Step-by-step explanation:

Applying,

`2^(n')` = R/R'............... Equation 1

Where n' = number of halflives that have passed, R = Original atom of the substance, R' = atom of the substance left after decay.

From the question,

Given: R = 40 atoms, R' = 5 atoms

Substitute these values into equation 1

`2^(n')` = 40/5

`2^(n')` = 8

`2^(n')` = 2³

Equation the base,

n' = 3