Suppose we consider a large number of continers each containing initially `10000` atoms of a radioactive material with a half life of `1` year. After `1` year.

Options

A. all the containers will have 5,000 atoms of the material.
B. all the containers will contain the same number of atoms of the material but that number will only be approximately 5,000
C. the containers will in general have different numbers of the atoms of the material but their average will be close to 5,000.
D. none of the containers can have more than 5000 atoms.

Answer

C

Explanation

Half-life time for a radio-active substance is defined as the time in which a radio-active atomic substance remains half of its original value of radio-active atom.
Given that
Half-life = 1 year.
So, after 1 year means one half-life, that is average atoms of radioactive substance remain after 1 year in each container is equal to half of 10,000 = 5,000 atoms (average).