Half Life

Half Life

Multiple Choice

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

Multiple Choice

Imagine you have 50,000 atoms of uranium-238. If U-238 has a half-life of 4.5 billion years, how many U-238 atoms will be left after 4.5 billion years?

• 25,000

• 50,000

• 12,500

• 0

Multiple Choice

If 10 mg of iodine 131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.

• 1.25mg

• 1.25g

• 10g

• 10mg

Multiple Choice

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

• 1/2

• 1/3

• 1/16

• 1/8

Multiple Choice

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

• 100%

• 75%

• 50%

• 25%

Multiple Choice

What is the half-life of iodine-131?

• 32 days

• 8 days

• 16 days

• 24 days

Multiple Choice

The time it takes for a radioactivity level to drop by a half is is the sample's ___________________.

• quarter life

• whole life

• wonderful life

• half life

Multiple Choice

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