Half Life Practice

Front

What is half-life?

Back

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

Front

How much of a sample remains after one half-life?

Back

After one half-life, 50% of the original sample remains.

Front

How much of a sample remains after two half-lives?

Back

After two half-lives, 25% of the original sample remains.

Front

How much of a sample remains after three half-lives?

Back

After three half-lives, 12.5% of the original sample remains.

Front

If the half-life of a substance is 8 days, how much of a 10 mg sample remains after 24 days?

Back

1.25 mg remains after 24 days.

Front

What is alpha decay?

Back

Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle, consisting of 2 protons and 2 neutrons.

Front

What is beta decay?

Back

Beta decay is a type of radioactive decay in which a beta particle (an electron or positron) is emitted from an atomic nucleus.

Front

If the half-life of uranium-232 is 70 years, how many half-lives are needed to reduce 10 g to 1.25 g?

Back

It takes 3 half-lives to reduce 10 g of uranium-232 to 1.25 g.

Front

How long does it take for Fermium-253 to be considered completely decayed after 10 half-lives if its half-life is 0.334 seconds?

Back

It takes 3.34 seconds for Fermium-253 to be considered completely decayed.

Front

What fraction of a sample remains after four half-lives?

Back

After four half-lives, 6.25% of the original sample remains.