1. A given radioactive sample emits only one type of radiation. When placed in a counter for 10 minutes, 1632 counts are registered.

Then the sample is removed and a background of 2641 counts is registered in 90 minutes.

a) What is the net count per minute?

b) If the efficiency of the counter is 26% what is the activity of the source in Bq?

b) What is the standard deviation of the activity (in Bq)?

2. Calculate the commutator [l², l^z]. Use the properties [AB,C]=A[B,C] + [A,C]B and

[A,BC]=B[A,C] + [A,B]C along with the definition of l² and lz.

3. Compare the proton separation energy for a nucleus with magic Z with that of its neighbours with Z+1 and Z-1. Discuss your findings.

4. Determine ΔB (A,Z)=B^exp (A,Z) - B^theor (A,Z), where B^theor (A,Z) is calculated using the semiempirical formula and B^exp (A,Z) using atomic masses. Do this for three nuclei with both proton and neutron magic numbers. Choose three nuclei: a light, a medium heavy and a heavy nucleus.

Discuss your findings.