radioactivity and half-life

Front

What is radioactivity?

Back

Radioactivity is the process by which unstable atomic nuclei lose energy by emitting radiation.

Front

What is half-life?

Back

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

Front

If 10 mg of iodine-131 is given to a patient, how much is left after 8 days? (Half-life = 8 days)

Back

5.0 mg

Front

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

Back

100 years

Front

After the third half-life, how much of the sample is left?

Back

1/8 of the original sample.

Front

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 2.4 minutes?

Back

50.0 g

Front

What is radioactive decay?

Back

Radioactive decay is the process by which unstable atoms emit radiation until they become stable.

Front

How do you calculate the remaining amount of a radioactive substance after multiple half-lives?

Back

Divide the initial amount by 2 for each half-life that has passed.

Front

What happens to the radioactivity of a substance after one half-life?

Back

The radioactivity is reduced to half of its original value.

Front

What is the significance of half-life in medicine?

Back

Half-life helps determine how long a radioactive substance remains active in the body.