Radioactive Decay

How many grams of Carbon-14 will remain after 17,100 years?

• 32 g

• 16 g

• 8 g

• 4 g

Tags

NGSS.HS-PS1-8

How many half-lives have passed if 12.5% ¹⁴C remains?

• 1 Half-life

• 2 Half-lives

• 3 Half-lives

• 4 Half-lives

Which index fossil would Carbon-14 be best for finding the absolute age?

• 1

• 2

• 3

• 4

Tags

NGSS.HS-LS4-1

What percentage of Rubidium-87 will remain after 4 half-lives?

• 25%

• 12.5%

• 6.25%

• 3.125%

Tags

NGSS.HS-PS1-8

The shaded boxes represent the undecayed atoms for Isotope "X". If Isotope X has a half-life of 1,000 years, how old is this sample?

• 1,000 years

• 2,000 years

• 3,000 years

• 4,000 years

Tags

NGSS.HS-PS1-8

How long does it take a 180-gram of gold-198 to decay to 22.5 grams if the half -life of gold-198 is 2.68 days?

• 8.04 days

• 3 days

• 4 days

• 2.68 days

Tags

NGSS.HS-PS1-8

How long will it for a take for a 40 gram sample ofcobalt-60 to decay to 5 grams? The half-life of cobalt-60 is 5.26 years.

• 17.75 days

• 15.78 years

• 15.15 years

• 17.17 years

How many neutrons are in this isotope of Uranium?

• 235
• 92
• 327
• 143

Tags

NGSS.HS-PS1-7

The half-life of Zn-71 is 2.4 minutes. Starting with 100.0 g, how many grams would remain after 7.2 minutes?

• 100.0 g

• 50.0 g

• 12.5 g

• 8.5 g

Tags

NGSS.HS-PS1-8

The half-life of strontium-90 is 25 years. How much will remain after 100 years if the initial amount is 4.0 g?

• 3.0 g

• 0.25 mg

• 0.3 g

• 6.25 g

Tags

NGSS.HS-PS1-8