Half Life Practice

After the third half-life, how much of the sample is left?

• 1/2
• 1/3
• 1/16
• 1/8

Tags

NGSS.HS-PS1-8

The half life of a sample is 5 days. How many half lives have passed in a period of 15 days?

• 1

• 2

• 3

• 4

What is the half life of this sample?

• 2 mins

• 3 mins

• 4 mins

• 4 hours

Tags

NGSS.HS-PS1-8

How old is this fossil after undergoing 4 half-lives?

Based on the graph, what is the approximate number of radioactive atoms of Isotope X that are present when 4 hours of decay has occurred?

• 1000

• 500

• 400

• 50

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

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

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%

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?

• 100.0g
• 50.0g
• 12.5g
• 8.5g

 Fermium-253 has a half-life of 0.334 seconds. A radioactive sample is considered to be completely decayed after 10 half-lives. How much time will elapse for this sample to be considered gone?

• 0.334 seconds
• 3.34 seconds
• 1.77 seconds
• 13.4 seconds

Tags

NGSS.HS-PS1-8