Half-Life

Front

What is Half-life?

Back

The amount of time it takes for half the nuclei in a sample of the isotope to decay.

Front

You have 100 grams of radioactive C-14. The half-life of C-14 is 5730 years. How many grams are left after 1 half-life?

Back

50 grams.

Front

The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g?

Back

0.25g.

Front

If 10 mg of iodine-131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.

Back

1.25mg.

Front

When nuclei decay, what is released?

Back

Energy.

Front

What does the term 'radioactive decay' mean?

Back

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

Front

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

Back

Remaining amount = Initial amount × (1/2)^(number of half-lives).

Front

How does the half-life of a substance affect its stability?

Back

A shorter half-life indicates a less stable isotope, as it decays more quickly.

Front

What is the significance of half-life in carbon dating?

Back

Half-life is used to determine the age of ancient organic materials by measuring the remaining C-14.

Front

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

Back

The mass decreases as the substance decays into other elements.