Half-Life of Rocks

If the half-life of uranium-232 is 70 years, how many half-lives will it take for 10 g of it to be reduced to 1.25 g?

• 1 half-life
• 2 half-lives
• 3 half-lives
• 4 half-lives

Earth elements decay and change into another element in a process called_____________.

• radiation

• isotope

• radioactive decay

• half-life

Geologist use the time it takes for a radioactive isotope to decay to half its original mass called a___________.

• radioactive decay

• isotope

• half-life

• carbon dating

The __________of rocks is the numerical age and real age of rocks.

• relative age

• half-life

• absolute age

• earth age

All organisms contain the element_________, so it is used to find the ages of fossils.

• carbon-14

• carbon-12

• carbon

• carbon age

How does absolute age differ from relative age?

• only absolute dating indicates which rock is older than another
• only absolute dating finds the age in years
• only relative dating finds the age in years

Geologists use radioactive dating to determine THE ABSOLUTE AGE OF ROCKS.

• True
• False

The original element that undergoes radioactive decay is known as the...

• daughter element
• half-life
• parent element
• carbon-14

The element that is the product of radioactive decay is known as the...

• daughter element

• half-life

• parent element

• carbon-14

If you had 1000 atoms of parent isotope, then how many parent atoms would you have after 3 half-lives?

• 75 atoms

• 250 atoms

• 500 atoms

• 125 atoms