EXERCISES ON RADIOACTIVITY
1. A radioisotope decays from 150 mg to 120.2 mg in 5 days. Calculate the
half-life of this isotope.
2. Iodine-131 has a half-life of 8 days. What is the mass of this nuclide
that remains when 40 g of it decays in 48 hours?
3. 3. A sample of Pd-100 decayed to a mass of 30 mg in 16 days. Given that
the half-life of Pd is 4 days, calculate the initial mass of the sample
4. 4. Given that 50.0 g of C-14 decayed in 4 half-lives, how much of this
isotope is left? C-14 Half-Life = 5730 Years.
5. A certain radioisotope has a half-life of 9 days. What percentage of an
initial mass of this isotope remains after 25 days?
6. A radioactive source has a half-life of 80 s. How long will it take for 5/6
of the source to decay?
7. A radioactive source has a half-life of 80 s. How long will it take for 5/6
of the source to decay?
8. Archaeologist dated Holy shroud using radiocarbon (
that the amount of
C), he found out
14
C found in Holy shroud is 92 % of that in the living
14
tissue (half-life of carbon-14=5730 years)
a) Calculate the decay constant for C14 assuming that it decreases
solely due to nuclear decay
b) Calculate the age of Shroud of Turin
9. The activity of a radioactive source decreased from 6000 per minute to
500 counts per minute in 10 hours. Calculate the half-life of the
radioactive source.