Nuclear Physics Tutorial

Nuclear Physics Tutorial

By Bertram Lim

Open Ended

15a) Explain what is meant by

(i) spontaneous decay

(ii) random decay

Draw

15ci)

Sr-90 undergoes beta decay to form Y.

Y undergoes beta decay to form Zr which is stable.

Complete the nuclear equations below for the decay of Sr-90 to form Zr

Draw

15cii) The half-life of Yttrium is 65 hours. Calculate the decay constant and give your answer in SI units.

Draw

15di) The half-life of Sr-90 IS 28 years. Calculate the fraction of the Sr-90 that remains after 50 years.

Open Ended

15dii) Despite the presence of some yttrium in the sample, the number of zirconium

nuclei is almost equal to the number of strontium nuclei that have decayed. By reference to the half-lives, explain this observation.

Open Ended

16a) Suggest why the determination of Phosphorus-32 by this method requires that the product of the decay be stable.

Open Ended

16aii) Suggest why the student did not need to make an allowance for background radiation.

Open Ended

16c) Explain why, although the count rates are too low for the radiation to cause

immediate symptoms in the student, careful shielding of the source is necessary.