Half-Life

Front

What is Half-life?

Back

The amount of time it takes for half the nuclei in a sample of the isotope to decay.

Front

Which isotope has the longest half-life?

Back

Uranium-238.

Front

If a radioactive isotope has a half-life of 10 years, how much of a 20g sample will remain after 30 years?

Back

2.5g.

Front

If 10 mg of iodine-131 is given to a patient, how much is left after 24 days? (Half-life of iodine-131 is 8 days)

Back

1.25mg.

Front

Barium-122 has a half-life of 2 minutes. If a fresh sample weighing 80 g was obtained, how much barium-122 will be left after 10 minutes?

Back

2.5g.

Front

What does it mean when we say an isotope is radioactive?

Back

It means that the isotope's nuclei are unstable and will decay over time, emitting radiation.

Front

How do you calculate the remaining amount of a radioactive substance after a certain time?

Back

Use the formula: Remaining amount = Initial amount × (1/2)^(time elapsed / half-life).

Front

What is the half-life of Carbon-14?

Back

Approximately 5730 years.

Front

Why is understanding half-life important in fields like medicine?

Back

It helps determine how long a radioactive substance will remain effective in treatments and diagnostics.

Front

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

Back

It reduces to half of its previous amount.