Half Life Calculations

What is the Half life of this isotope?

• 5 seconds

• 10 seconds

• 15 seconds

• 20 seconds

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NGSS.HS-PS1-8

You have 100 grams of radioactive C-14. The half life of C-14 is 5730 years. 
How many grams are left after 1 half life? 

• 100 grams
• 25 grams
• 2 grams
• 50 grams

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NGSS.HS-PS1-8

What is Half-life?

• The amount of time it takes for some of the nuclei in a sample of the isotope to decay
• The amount of time it takes for half the electrons in a sample of the isotope to decay
• The amount of time it takes for half the nuclei in a sample of the isotope to decay
• the amount of time it takes to double the nuclei in a sample of the isotope to decay

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NGSS.HS-PS1-8

The half life of iodine-131 is 8.040 days. What percentage of an iodine-131 sample will remain after 40.20 days?

• 312.5%
• 31.25%
• .3125%
• 3.125%

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NGSS.HS-PS1-8

If the half-life of uranium-232 is 70 years, how many half-lives will it take for 10 g of it to be reduced to 1.25 g?

• 1 half-life
• 2 half-lives
• 3 half-lives
• 4 half-lives

Tags

NGSS.HS-PS1-8

What percentage of rubidium-87 atoms will be left after four half lives?

• 25.0%

• 12.5%

• 6.25%

• 3.125%

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NGSS.HS-PS1-8

What is the half-life of iodine-131?

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

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NGSS.HS-PS1-8

What is the Half Life of this isotope?

• 3 days

• 5 days

• 8 days

• 10 days

Tags

NGSS.HS-PS1-8

¹⁴₆C has a half life of 5730 years, how many years would it take the 4.0 g sample to decay to 0.25 g?

• 4 years
• 5730 years
• 22,920 years
• 28,650 years

Tags

NGSS.HS-PS1-8

The % of the parent isotope remaining after 1 Half Life.

• 50%

• 25%

• 12.5%

• 6.25%

Tags

NGSS.HS-PS1-8