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WorksheetsRadioactive Half Life
Total questions: 15
Worksheet time: 12mins
What is a becquerel (Bq)?
One decay per second
One decay per minute
One decay per hour
What is the half-life of a radioactive isotope?
The time taken for the daughter nuclei to increase
The time taken for the nucleus to decay
The time taken for half the parent nuclei to decay
Which radioactive isotopes is most suitable tracer to monitor blood flow in a heart?
Americium-237
alpha , and a half-life of 78 minutes
Technetium-99m
gamma, and a half-life of 6 hours
Krypton-78
beta and a half-life of 10.7 years
A radioactive source’s activity falls from 128 Bq to 8 Bq in 20 hours. What is it's half-life?
5 hours
10 hours
30 minutes
Which isotopes would be used in a machine for measuring paper thickness?
An alpha source with a short half-life
A beta source with a long half-life
A gamma source with a long half-life
What percentage of a polonium sample will remain after three half-lives?
6.25%
12.5%
25%
Living wood has a 14C activity of 120 Bq. Ancient wood has an activity of 30 Bq. The half-life of 14C is 5,730 years. Estimate the age of the ancient wood.
5,730 years
11,460 years
17,190 years
What isotope should be injected directly into cancer to treat it ?
An alpha emitter with a short half-life
A beta emitter with a short half-life
A gamma emitter with a short half-life
What is the best radioactive source for measuring the amount of crisps poured into packaging?
A gamma source with a short half-life
A beta source with a long half-life
An alpha source with a short half-life
A radioactive substance has a half-life of 30 minutes.
What fraction of the atoms will not have decayed after 1 hour?
1/2
1/4
1/3
A radioactive source has a 200 Bq count at 12:00. At 15:00, the count is 25 Bq. What is its half-life?
60 minutes
30 minutes
15 minutes
Iodine-131 contaminated rainwater has a count rate of 1200 Bq. The half-life of iodine-131 is 8 days. How many days it will take for the count rate to fall to 75 Bq.
16 days
24 days
32 days
Which of the three types of radiation is the most strongly ionising?
alpha (α)
beta (β)
gamma (γ)
Why are radioactive isotopes with 2 second half-lives not used as medical tracers?
It would be too ionising
It would decay before a scan could be taken
It's too hazardous for the medical staff
Why does alpha decay cause an atom to become a different element?
The number of protons decrease
The number of neutrons decrease
The number of electrons decrease
