2014 Med Phys I Lecture 2.1 PreTest Question Title * 1. Name: Question Title * 2. Which type of decay produces radiation that penetrates furthest? alpha beta gamma internal conversion Question Title * 3. An excited nucleus decayed by internal conversion. What happens in internal conversion? The excited nucleus gives its energy to an electron (usually K shell). The kinetic energy of the electron is the energy of nuclear excitation minus the binding energy of the electron. The electron hole that remains can create characteristic x-rays or Auger electrons. The nucleus produces an energetic positron and neutrino. Later, the positron can annihilate an electron. The nucleus is really a small vehicle. Internal conversion is the nuclear version of an internal combustion engine. The nucleus converts from an excited state to the ground state using a gamma ray. Question Title * 4. What is the minimum required mass defect for an isotope to undergo positron decay? 0.511 MeV 1.022 MeV 2.99 MeV 931.5 MeV Question Title * 5. Alpha particles are typically emitted from what type of nuclei Light nuclei Medium mass nuclei Heavy nuclei Question Title * 6. Which nuclear decay process decreases the Z number by 2 and the A number by 4? Alpha Decay Beta Decay Electron Capture Question Title * 7. Are there any issues that are not clear to you at this time? Done