Front

What is half-life?

Back

The time it takes for a radioactive isotope to decay to half its original mass.

Front

How much of a sample is left after one half-life?

Back

1/2 of the original sample.

Front

If a sample has gone through three half-lives, how much of the original sample remains?

Back

1/8 of the original sample.

Front

What is the half-life of iodine-131?

Back

8 days.

Front

If you start with 10 mg of iodine-131, how much is left after 24 days?

Back

1.25 mg.

Front

How many half-lives does it take for a sample to be considered completely decayed?

Back

After 10 half-lives.

Front

If the half-life of uranium-232 is 70 years, how many half-lives to reduce 10 g to 1.25 g?

Back

3 half-lives.

Front

What is the formula to calculate remaining mass after n half-lives?

Back

Remaining mass = Initial mass * (1/2)^n.

Front

What happens to the mass of a radioactive substance over time?

Back

It decreases as it decays into other elements.

Front

What is radioactive decay?

Back

The process by which an unstable atomic nucleus loses energy by radiation.