6.3 Half-Life

Front

What is half-life?

Back

Half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

What is the half-life of iodine-131?

Back

8 days.

Front

What is the half-life of strontium-90?

Back

25 years.

Front

If you start with 50,000 atoms of uranium-238, how many will remain after one half-life?

Back

25,000 atoms.

Front

How much of a 250g sample remains after 5 half-lives?

Back

7.81g.

Front

If you have 12 kg of Polonium and it undergoes two half-lives, how much is left?

Back

3 kg.

Front

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

Back

It decreases exponentially as it undergoes decay.

Front

How do you calculate the remaining amount after multiple half-lives?

Back

Use the formula: Remaining amount = Initial amount / (2^n), where n is the number of half-lives.

Front

What is the significance of half-life in medicine?

Back

It helps determine how long a radioactive substance remains effective in treatments.

Front

How does half-life relate to radioactive dating?

Back

Half-life is used to estimate the age of materials by measuring the remaining radioactive isotopes.