Question 1 options:
Radioactivity is caused by the decay of the nucleus which occurs when unstable nuclei lose protons and neutrons. This quiz will look at the time it takes for a specific amount of radioactive material to decay, which is measured in a unit called half-life.

If you are given the half-life for the decay of a particular radioisotope, then you can calculate how much of that radioisotope remains after several half-lives:
fraction remaining (FR) = 1/2n

where n=number of half-lives

Knowing this, what is the fraction equivalent of 2 half-lives?