Half Life

¹⁴₆C has a half-life of 5730 years how many grams of a 4.0 g sample would be left after 3.5 half-lives?

• 1.0 g
• 0.5 g
• 0.38 g
• None would be left

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

A radioisotope of silver has half life of 10 minutes. What fraction of the original mass would remain after one hour?

• 1/64
• 1/2
• 1/4
• 1/8

Tags

NGSS.HS-PS1-8

A radioactive substance decays with a half life of 12,000 years. If the substance is stored for 36000 years, then what fraction of it remains? 

• 1/2
• 1/8
• 1/24
• 1/64

Tags

NGSS.HS-PS1-8

An isotope of cesium (cesium-137) has a half-life of 30 years. If 1.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain? 

• 0.5 mg
• 0.25 mg
• 0.125 mg
• 0.0625 mg

Tags

CCSS.HSF.LE.A.4

A 2.5 gram sample of an isotope of strontium-90 was formed in a 1960 explosion of an atomic bomb at Johnson Island in the Pacific Test Site. The half-life of strontium-90 is 28 years. In what year will only 0.625 grams of this strontium-90 remain? 

• 1988
• 2016
• 2044
• 2072

Tags

NGSS.HS-PS1-8

Actinium-226 has a half-life of 29 hours. If 100 mg of actinium-226 disintegrates over a period of 58 hours, how many mg of actinium-226 will remain? 

• 50 mg
• 25 mg
• 12.5 mg
• 6.25 mg

Tags

CCSS.HSF.LE.A.4