1. Antimatter  The mass of a p is 938MeV/c 2 and its charge is +e. The mass of a  p is __ and its charge is ___ a ) 938MeV/c 2, +e b ) - 938MeV/c 2, +e c ) 938MeV/c 2, -e d) - 938MeV/c 2, -e

2. Hadrons  A particle made up of an up, charm, and strange quark is a __ with a charge of ___ a ) baryon, +1 b ) baryon, 0 c ) meson, +1 d) meson, -1

3. PET In PET, a positron is emitted. Suppose it has a kinetic energy of 50 keV. It immediately annihilates with one of the electrons in a nearby atom (approximately at rest), producing two photons. 1)Find the total energy of the electron and positron. 1072 keV 2)What is the total energy of the two photons? 1072 keV 3)Find the average energy of each photon emitted. 536 keV 4)Find the wavelength of a photon with this average energy. 0.00231 nm 5)Is it a photon of visible light? Justify. No, much smaller wavelength than visible light (which is 400- 700nm). It is gamma.