Half Life Practice HLE

Front

What is half-life?

Back

The amount of time when half of the material has decayed.

Front

What is the half-life of iodine-131?

Back

8 days.

Front

If you start with 100.0 g of Zn-71, how much is left after 3 half-lives?

Back

12.5 g.

Front

After the third half-life, what percentage of the sample is left?

Back

12.5%.

Front

If 10 mg of iodine-131 is given, how much is left after 16 days?

Back

2.5 mg.

Front

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

Back

Remaining amount = Initial amount × (1/2)^n.

Front

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

Back

It decreases exponentially.

Front

Define radioactive decay.

Back

The process by which an unstable atomic nucleus loses energy by radiation.

Front

What is the significance of half-life in medicine?

Back

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

Front

How does half-life relate to the stability of isotopes?

Back

Shorter half-lives indicate less stability and faster decay.