Question

If a rock sample has a half-life of 10 years, and has 100 atoms of parent materi today, how many half-lives will have passed before it has only 25 atoms of parent material left Explain your reasoning

Answer 1

2

Step-by-step explanation:

The half-life of a radioactive material is the time taken for a nuclide to decay to half its original composition.

Given:

Half-life = 10yrs

Number of atoms in parent = 100atoms

Unknown:

Number of half-lives what will pass for 25 atoms to remain:

Start First half life Second half life

Number of years 0 10 20

Number of atoms 100 50 25

The number of half-lives that will pass is 2