Half-life Flashcards
What is half-life?
The time taken for the quantity of a radioactive substance to reduce to half its initial amount.
True or False: The half-life of a substance is constant.
True
If a substance has a half-life of 5 years, how much of a 100g sample remains after 15 years?
12.5g
Fill in the blank: The half-life of a radioactive isotope is usually measured in __________.
seconds, minutes, hours, days, or years
What is the formula to calculate the remaining amount after a certain number of half-lives?
Remaining amount = Initial amount × (1/2)^(number of half-lives)
What is the unit of measurement for half-life?
Time (seconds, minutes, hours, etc.)
What happens to the amount of a radioactive substance after one half-life?
It decreases to half of its initial amount.
True or False: After two half-lives, a sample will be 25% of its original amount.
True
How many half-lives are required for a substance to decay to 1/8 of its original amount?
Three half-lives
If the half-life of Carbon-14 is 5730 years, how long will it take for a sample to decay to 1/16 of its original amount?
22,920 years
What does a shorter half-life indicate about a radioactive isotope?
It decays more quickly.
Multiple Choice: Which of the following has the longest half-life? A) Uranium-238 B) Polonium-210 C) Radon-222
A) Uranium-238
What is a common application of half-life in medicine?
Radiotherapy for cancer treatment.
Fill in the blank: The __________ of a radioactive isotope affects how long it can be used in medical applications.
half-life
True or False: Half-life can vary based on environmental conditions.
False
What is the relationship between half-life and radioactive decay?
Half-life is the time it takes for half of the radioactive atoms to decay.
How is half-life used in carbon dating?
By measuring the remaining Carbon-14 in a sample to estimate its age.
Multiple Choice: If a sample has a half-life of 10 years, how much of a 200g sample remains after 30 years? A) 50g B) 25g C) 100g
B) 25g
What is the term for the process of a radioactive substance losing particles?
Radioactive decay
True or False: All radioactive isotopes have the same half-life.
False
Fill in the blank: The half-life of a substance can be determined by measuring its __________ over time.
activity
What is the significance of half-life in nuclear waste management?
It helps determine how long waste remains hazardous.
How does the concept of half-life apply to the safety of nuclear power?
It informs how long radioactive materials will remain dangerous.
What is the half-life of Iodine-131?
Approximately 8 days
Multiple Choice: Which isotope is used in medical imaging and has a relatively short half-life? A) Cobalt-60 B) Technetium-99m C) Uranium-235
B) Technetium-99m
