Absolute Dating Calculations

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 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

The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____.

• the daughter product
• geologic time
• the half-life
• the half-time

Tags

NGSS.HS-PS1-8

If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives?

• 25 years
• 200 years
• 400 years
• 800 years

Tags

CCSS.HSF.LE.A.4

If 10 mg of iodine 131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.

• 1.25mg
• 1.25g
• 10g
• 10mg

Tags

CCSS.HSF.LE.A.4

What percent of carbon-14 would be left after 11,460 years? (2 half lives)

• 100%
• 75%
• 50%
• 25%

Tags

CCSS.HSF.LE.A.4

To determine when a volcano erupted, Michael used a sample of a mineral that formed when the lava cooled and became solid rock. He measured the amount of argon-40 in the sample to find how much potassium-40 had decayed since the rock formed. What else would Michael need to know to find the age of the mineral in years?

• the half-life of potassium-40

• the amount of energy released

• the mass of a potassium-40 atom

• the time it takes argon-40 to decay

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 graph shows the radioactive decay of a 50-gram sample of a radioactive isotope. 
According to the graph, what is the half-life of this isotope? 

• 100 years
• 150 years
• 200 years
• 300 years

Tags

NGSS.HS-PS1-8

Scientists use radioactive decay to measure...

• relative time

• Age in years

• half-lives

• time of day

Tags

NGSS.HS-PS1-8