Question

You analyze a sample of a meteorite that landed on Earth and find that 15/16 of a certain type of radioactive atoms have decayed into the corresponding daughter atom. Calculate the number of half-lives that have occurred.

Answer 1

Answer:

The number of half-lives that have occurred are 4.

Explanation:

Formula used for number of half lives :

$a=\frac{a_o}{2^n}$

where,

a = amount of reactant left after n-half lives

$a_o$ = Initial amount of the reactant

n = number of half lives

$a_o=x$

$a = x-\frac{15}{16}x=\frac{1}{16}x=a$

$\frac{1}{16}x=\frac{x}{2^n}$

$2^n=16=2^4$

n = 4

The number of half-lives that have occurred are 4.