Half-Life Review

Front

What is half-life?

Back

Half-life is the time required for a quantity to reduce to half its initial amount, commonly used in the context of radioactive decay.

Front

What is the half-life of iodine-131?

Back

8 days.

Front

What happens to an unstable isotope over time?

Back

It undergoes radioactive decay.

Front

If an isotope has a half-life of 3 days, how much of a 100g sample remains after 9 days?

Back

12.5g.

Front

What is the half-life of barium-122?

Back

2 minutes.

Front

How much barium-122 remains from an 80g sample after 10 minutes?

Back

2.5g.

Front

What is the significance of half-life in geology?

Back

Geologists use half-life to date rocks and fossils by measuring the decay of radioactive isotopes.

Front

Why do some elements have half-lives?

Back

They are unstable and undergo radioactive decay.

Front

What is the formula to calculate remaining mass after a certain number of half-lives?

Back

Remaining mass = Initial mass * (1/2)^(number of half-lives).

Front

How does the half-life of a substance affect its use in medical applications?

Back

Short half-lives are preferred for diagnostic imaging, while longer half-lives are used for treatment.