Half Life Problems

If a sample starts with 1,000 undecayed nuclei and after 20 minutes it has 500 undecayed nuclei, what is the half-life?

• 10 minutes

• 20 minutes

• 30 minutes

• 40 minutes

What is the relationship between the rate of decay and the length of the half-life?

• The rate of decay is directly proportional to the length of the half-life

• The rate of decay is unrelated to the length of the half-life

• The rate of decay is equal to the length of the half-life

• The rate of decay is inversely proportional to the length of the half-life

Tags

NGSS.HS-PS1-8

What is the relationship between decay and half-life?

• Decay is the process by which half-life occurs

• Decay is the process that determines the length of half-life

• Decay is unrelated to half-life

• Decay is the result of half-life

Tags

NGSS.HS-PS1-8

What can half-life be used for?

• To determine the number of nuclei in a sample

• To predict when a nucleus will decay

• To solve problems related to radioactive isotopes

• To measure the rate of decay

Tags

NGSS.HS-PS1-8

What does a longer half-life indicate?

• faster rate of decay

• doubling rate of decay

• slower rate of decay

• constant rate of decay

Tags

NGSS.HS-PS1-8

What is the half-life of a radioactive isotope?

• The time it takes for the number of nuclei to remain constant

• The time it takes for the number of nuclei to double

• The time it takes for the number of nuclei to halve

• The time it takes for the number of nuclei to triple

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 is the Half life of this isotope?

• 5 seconds

• 10 seconds

• 15 seconds

• 20 seconds

Tags

NGSS.HS-PS1-8

What is the Half Life of this isotope?

• 3 days

• 5 days

• 8 days

• 10 days

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