I and ii only 2 iii only 3 i ii and iii 4 i and iii

This preview shows page 9 - 10 out of 10 pages.

1.I and II only2.III only3.I, II, and III4.I and III only5.II onlycorrectExplanation:The kinetic energy of the initial (thermal)neutron is negligible.Nuclear reactions have many channels (dif-ferent products), so statement I is false.The nucleon number is conserved, so state-ment III is false.Because of conservation of energy and thefact that the end products carry kinetic en-ergy and/or additional energy in terms ofβrays (electrons,etc.)andγrays (photons),the rest energy of the product must be lessthan that of the initial particles.02710.0pointsIthasbeenestimatedthatEarthhas9.1×1011kg of natural uranium that canbe economically mined. Of this total, 0.70%is235U.
If all the world’s energy needs (7×1012J/s)were supplied by235U fission, how long wouldthis supply last?
yu (xy3236) – Homework 10 – yao – (54785)10Δt=EtotP=NRP=mUmU235·RP=0.007 (9.1×1011kg)3.9×1025kg/atom×2.08×108eV/event7×1012J/s×1.6×1019J1 eV=7.76533×1010s.02810.0pointsHow much extra kinetic energy is provided bythe following fusion reaction?11H +21H-→32He +γThe mass of11H is 1

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture