Radioactivity and Half Life

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

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

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

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

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

• 1/2
• 1/3
• 1/16
• 1/8

When nuclei decay, massive amounts of __________ is released.

• energy
• electrons
• protons
• neutrons

Where does radioactivity have application in our lives?

• Medicine
• Energy (electricity)
• Agriculture
• All of the above

In a nuclear reactor, electricity is produced from what element?

• Plutonium
• Uranium 235
• Radon 220
• Lead 232

The three types of nuclear radiation in order of increasing penetrating power are

• alpha, beta, gamma
• alpha, gamma, beta
• beta, alpha, gamma
• gamma, alpha, beta

what's the half life of this substance?

• 1 day
• 2 days
• 3 days
• 4 days