Question

A sample contains 10 g of a radioactive isotope. how much radioactive isotope will remain in the sample after 3 half-lives?

Answer 1

1.25 g of radioactive isotope will remain in the sample after 3 half-lives.

Step-by-step explanation:

Formula used to calculate the number of half life elapsed :

`N=(N_o)/(2^n)`

where,

N = amount of radioactive sample remains after n-half lives = ?

`N_o` = Initial amount of the radioactive sample= 10 g

n = number of half lives = 3

`N=(10 g)/(2^3)=1.25 g`

1.25 g of radioactive isotope will remain in the sample after 3 half-lives.