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

What is the half-life of uranium-232?

Back

70 years.

Front

If the half-life of an isotope is 10 seconds, how much of the original sample remains after 20 seconds?

Back

1/4 of the original sample.

Front

How many half-lives are in 100 years if the half-life of strontium-90 is 25 years?

Back

4 half-lives.

Front

What fraction of a radioactive substance remains after 3 half-lives?

Back

1/8 of the original amount.

Front

If you start with 8 g of a substance with a half-life of 5 years, how much will remain after 15 years?

Back

1 g.

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

If a sample has decayed to 1/4 of its original amount, how many half-lives have passed?

Back

2 half-lives.

Front

What is the half-life of carbon-14?

Back

Approximately 5730 years.

Front

How do you determine the age of a bone sample using carbon dating?

Back

By measuring the remaining C-14 and comparing it to the original amount.