woveu Una . h, . . The bream of negative muons can be stopped in matter because a moon may be (a) absorbed by a 910\")\" Eff goes into an excited state; (b) transformed into an electron by emitting a photon or (c) captured by on 3w\"! l bound orbit about the nucleus. _\" . A relativistic proton loses 1.8 MeV when penetrating a 1 cm thick scintillator. which one of the following will\": is predominant, (a) ionization, excitation; (b) Compton effect, (c) Pair production. _ [For the relativistic proton beam passing through a medium, energy loss by ionization and excitation '3 \"'5' I - 2 MeV/gm (\"til2. Since the density of scintillator is p = i gin/cm}. therefore rb:(= 1cm} = 1 gm \"(2' W dex = [.8 Mall/gm cm", which agrees with ionization loss rate. I . The mean energy loss of a relativistic charged particle in matter per gin/cm2 is about (a) 500 2V. (1?) 10 it\" (C) 2 MeV, (d) 1 GeV. (4:) . The critical energy of an electron is the energy at which (a) the electron ionizcs an atom. (b) the radiation 1: equals the lonimliml 1085. (c) the threshold of nuclear reaction is reached. I . The straggling of heavy ions at low energy is mostly a consequence of (a) nite momentum. (b) ucmadng SW of ionization, to) multiple scattering. (d