Radioactive Dating

The graph shows the generalized rate of decay of radioactive isotopes over 5 half-lives.
If the original mass of a radioactive isotope was 24 grams, how many grams would remain after 3 half-lives?

• 12

• 24

• 3

• 6

Tags

NGSS.HS-PS1-8

Average numerical age, in years of a rock or object.

• Absolute Age

• Relative Age

Tags

NGSS.HS-ESS1-5

How long would it take for there to be only 25% of the parent isotope left?

• 100

• 25

• 50

• 75

Tags

NGSS.HS-PS1-8

What is the half life of this sample?

• 100

• 25

• 50

• 75

Tags

NGSS.HS-PS1-8

Using your Earth Science Reference Table page 15, what element has the shortest half life?

• Uranium-238

• Uranium-235

• Potassium-40

• Carbon-14

Tags

NGSS.HS-PS1-8

Using your Earth Science Reference Table page 15, if Uranium-238 has undergone 2 half lives, how much time has elapsed?

• 4.5 billion

• 9 billion

• 713 million

• 9 million

Tags

NGSS.HS-PS1-8

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

• era

• age

• half-life

• eon

Tags

NGSS.HS-PS1-8

How many grams of Carbon-14 will remain after 17,100 years- C-14 has a half life 5,730 so 17,100 is about 3 half lives?

• 32 g

• 16 g

• 8 g

• 4 g

You find a rock sample with radioactive atoms present.  If 25% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)

• zero

• 1

• 2

• 3

Tags

NGSS.HS-PS1-8

The table shows the radioactive decay of carbon-14. Part of the table has been left blank.
After 22,800 years, approximately what percentage of the original carbon-14 remains?

• 15%

• 12.5%

• 6.25%

• 3.125%

Tags

NGSS.HS-PS1-8