Half-life

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

Tags

NGSS.HS-PS1-8

Barium-122 has a half-life of 2 minutes. A fresh sample weighing 80 g was obtained. If it takes 10 minutes to set up an experiment using barium-122, how much barium-122 will be left when the experiment begins?

• 0.25g
• 2.5g
• 25g
• 80g

Tags

CCSS.HSF.LE.A.4

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

• 3.0g
• 0.25mg
• 0.3g
• 0.25g

Tags

CCSS.HSF.LE.A.4

When nuclei decay, massive amounts of __________ is released.

• energy
• jello
• protons
• neutrons

Tags

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%

Tags

CCSS.HSF.LE.A.4

After 4 half-lives, 1g of a sample of Krypton-85 remains unchanged.  What was the original mass of the sample?

• 16g
• 32g
• 0.0625g
• 4g

Tags

NGSS.HS-PS1-8

What is the half-life of iodine-131?

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

Tags

NGSS.HS-PS1-8

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

• 100%
• 75%
• 50%
• 25%

Tags

NGSS.HS-PS1-8

What percent of carbon-14 would be left after 11,460 years?

• 100%
• 75%
• 50%
• 25%

Tags

NGSS.HS-PS1-8

If one-fourth of the carbon-14 is remaining then how many half-lives have passed?

• 1
• 2
• 3
• 4

Tags

NGSS.HS-PS1-8