Unit 5A Radioactivity

Front

What is the half-life of a radioactive element?

Back

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

Front

If a radioactive element has a half-life of 100 years, how long will it take for the radioactivity to reduce by one half?

Back

100 years.

Front

What type of nuclear reaction produces energy in the sun?

Back

Fusion.

Front

What is an example of a fission reaction?

Back

Splitting of a heavy nucleus into smaller nuclei, releasing energy.

Front

After three half-lives, how much of a radioactive sample remains if you start with 1 unit?

Back

1/8 of the original sample.

Front

What does the term 'decay' refer to in radioactivity?

Back

The process by which a radioactive substance transforms into a different substance, releasing energy.

Front

What is the rate at which a radioactive element decays called?

Back

Half-life.

Front

What happens to the amount of a radioactive substance after each half-life?

Back

It reduces to half of its previous amount.

Front

What is the difference between fusion and fission?

Back

Fusion combines light nuclei to form a heavier nucleus, while fission splits a heavy nucleus into lighter nuclei.

Front

What is a common use of radioactive isotopes in medicine?

Back

They are used in imaging and treatment, such as in cancer therapy.