Radiometric dating, fossils & Geologic Time Quiz Review

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

You find a rock sample with radioactive atoms present.  If 12.5% 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

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

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%

Which characteristic of carbon-14 dating helps scientists determine the approximate time a species became extinct?

• Carbon-14 is not present in more recent fossils
• Carbon-14 increases at a constant rate over time
• Carbon-14 decreases at a constant rate over time
• Carbon-14 can only be found in fossils of a certain period

What percent of carbon-14 would be left after 5730 years?

• 100%
• 75%
• 50%
• 25%

Tags

CCSS.HSF.LE.A.4

The Earth is estimated to be how old?

• 4.6 Million years old
• 6,000 years old
• 4.6 Billion years old
• Who knows

Carbon dating is only useful in dating organisms up to 50,000 years old because_______

• It has a short half-life, and most of the carbon-14 has not decayed in 50,000 years

• It has a long half-life, and all of the carbon -14 has decayed before the end of 50,000 years

• It has a short half-life, and all of the carbon-14 will decay by 50,000 years

• It has a long half-life, and all of the carbon-14 will be available after 50,000 years

What is the largest division of time?

• eon
• epoch
• era
• period

What forms when sediment fills in a cavity left by a dead organism?

• cast
• index
• trace
• mold