Front

What is Half-Life?

Back

The time required for half of the radioactive atoms in a sample to decay.

Front

What is the Half-Life of carbon-14?

Back

Approximately 5,730 years.

Front

How does radioactive decay occur?

Back

Radioactive decay occurs when unstable atomic nuclei lose energy by emitting radiation.

Front

What is the significance of Half-Life in dating geological samples?

Back

Half-Life allows scientists to determine the age of fossils and geological formations by measuring the remaining amount of a radioactive isotope.

Front

If a substance has a Half-Life of 10 days, how much of a 100g sample remains after 20 days?

Back

25g remains after 20 days.

Front

What happens to the stability of an isotope as it undergoes decay?

Back

It becomes more stable as it transforms into a different element or isotope.

Front

What is the Half-Life of iodine-131?

Back

8 days.

Front

How many Half-Lives are needed for a radioactive substance to decay to less than 1% of its original amount?

Back

It takes about 7 Half-Lives.

Front

What is the Half-Life of strontium-90?

Back

25 years.

Front

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

Back

0.25g remains after 100 years.