Half Life

What percentage of a radioactive substance will remain after 2 Half Lives?

• 50%

• 25%

• 12.5%

• 6.25%

What % of the parent radioactive isotope remains after 1 half life?

• 50%

• 25%

• 12.5%

• 6.25%

What type of decay is being illustrated in following picture? 

• beta decay
• alpha decay 

Tags

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

Tags

CCSS.HSF.LE.A.4

The original mass of a radioactive isotope is 600mg. If the half life is 2 hours, what will the mass of the isotope be after 4 hours?

• 600mg

• 300mg

• 150mg

• 75mg

The half life of a radioactive isotope is 10 minutes. What percentage of the isotope will be left after 30 minutes?

• 100%

• 50%

• 25%

• 12.5%

What fraction of a radioactive substance will be left after one half life?

• 1/2

• 1/4

• 1/3

• 1/8