Absolute Dating

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

What element is usually used to date fossils?

• uranium-235
• carbon-14
• mercury-203
• thorium-234

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

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

What is the half life of Carbon-14?

• 5730 yrs

• 1.2 billion years

• 713 million years

• 1.3 billion years

What type of absolute dating is based on counting the bands of light and dark sediment in rocks?

• Rate of Deposition

• Rate of Erosion

• Varve Count

• Radiometric Dating

What is the Half life of this isotope?

• 5 seconds

• 10 seconds

• 15 seconds

• 20 seconds

What type of absolute dating is based on the amount of material worn away over time?

• Rate of Deposition

• Rate of Erosion

• Varve Count

• Radiometric Dating

What is the half-life of iodine-131?

• 32 days
• 8 days
• 16 days
• 24 days

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