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

How is Half-life used in radioactive decay?

Back

Half-life is used to determine the time it takes for a radioactive substance to reduce to half its initial amount.

Front

If the half-life of an isotope is known, how can you calculate the remaining amount after a certain period?

Back

You can use the formula: Remaining amount = Initial amount * (1/2)^(time elapsed / half-life).

Front

What is the half-life of iodine-131?

Back

The half-life of iodine-131 is 8 days.

Front

How much of a 10 mg sample of iodine-131 remains after 24 days?

Back

1.25 mg.

Front

What is the half-life of strontium-90?

Back

The half-life of strontium-90 is 25 years.

Front

How much strontium-90 remains after 100 years if the initial amount is 4.0 g?

Back

0.25 g.

Front

What does it mean when we say an isotope has a half-life of 3 days?

Back

It means that after 3 days, half of the original amount of the isotope will have decayed.

Front

Can half-life be used to date archaeological finds?

Back

Yes, half-life is used in radiocarbon dating to estimate the age of organic materials.

Front

What factors affect the half-life of an isotope?

Back

The half-life of an isotope is a constant and is not affected by external conditions such as temperature or pressure.