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 strontium-90?

Back

The half-life of strontium-90 is 25 years.

Front

How do you 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

What is the half-life of iodine-131?

Back

The half-life of iodine-131 is 8 days.

Front

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

Back

After one half-life, half of the original amount of the substance remains.

Front

What is released when nuclei decay?

Back

Massive amounts of energy are released when nuclei decay.

Front

Why is carbon-14 useful in dating geological samples?

Back

Carbon-14 is useful because it decays at a regular rate, allowing scientists to determine the age of samples.

Front

If you start with 4.0 g of strontium-90, how much remains after 100 years?

Back

0.25 g of strontium-90 remains after 100 years.

Front

What is the significance of a substance's half-life in radioactive decay?

Back

The half-life indicates how quickly a radioactive substance will decay and helps in dating materials.

Front

What is the half-life of a substance that decays to 1/8 of its original amount after 24 years?

Back

The half-life is 8 years.