advertisement

PHY 102 NUCLEAR PHYSICS TUTORIAL 1. A 3.00 MeV 7Li nucleus moves towards a 232 92Th nucleus in what would have been a head-on collision. What is the least distance between the centres of the two nuclei? 2. Calculate the distance of closest approach for a head-on collision between a 5.30 MeV alpha particle and a copper nucleus. 3. Calculate the energy of disintegration, Q, when 235 92U decays by emitting an alpha particle. Will the decay be spontaneous or not? 4. What is the mass excess of 120Sn if its mass is 119.902 197 u? Express the mass unit of MeV/c2. 5. What is the binding energy per nucleon of the americium isotope 244 95Am? [Mass of Am-244 is 244.064 279 u, mass of neutron is 1.008665 u, mass of proton is 1.007 825 u.] 6. The half-life of a radionuclide is 27 days. How long will it take for the decay rate to fall to ¼ of its initial value? 7. Plutonium-239 has a half-life of 2.41 × 109 yr. What is the decay rate of 2.0 mg of this nuclide? 8. The radionuclide 64Cu has a half-life of 12.7 h. If a sample contain 5.50 g of initially pure 64Cu at 𝑡 = 0, how much of it will decay between 𝑡1 = 14h and 𝑡2 = 16h? 9. Calculate the disintegration energies for these hypothetical decay processes. 235 232 3 92U→ 90Th + 2He 235 231 4 92U→ 90Th + 2He Nuclide Mass 235.0429 u 232.0381 u 231.0363 u 3.0160 u 4.0026 u 10. A 75 kg person receives a whole-body radiation dose of 2.4 × 10-4 Gy, delivered by alpha particles for which the RBE factor is 12. Calculate (a) the absorbed energy in joules and (b) the dose equivalent in Sieverts. 235 92U 232 90Th 231 90Th 3 2He 4 2He