Question

6. One form of nuclear radiation, beta decay, occurs when a neutron changes into a proton, an electron, and a neutral particle called an antineutrino: n → pt + e + De, where ve is the symbol for an antineutrino. When this change happens to a neutron within the nucleus of an atom, the proton remains behind in the nucleus while the electron and neutrino are ejected from the nucleus. The ejected electron is called a beta particle. One nucleus that exhibits beta decay is the isotope of hydrogen H, called tritium, whose nucleus consists of one proton (making it hydrogen) and two neutrons (giving tritium an atomic mass m = 3u). Tritium is radioactive, and it decays to helium: 3H + 3He+ e +ve. (a) Is charge conserved in the beta decay process? Explain. (b) Why is the final product a helium atom? Explain. (c) The nuclei of both H and He have radii of 1.5 x 10-15 m. With what minimum speed must the electron be ejected if it is to escape from the nucleus and not fall back?
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Answer 1

ł the n 34 - ptt Het ē t de 21 He ap 2n in a) charge in beta le conservation - decay process of trituim nucles 3 Ho 3 Het è te

sight hand side: Co (We) Total charge = (2+) + (2-) + (6) = 4+ left hand side total charge = (1+) + (20) = 1 + (P) ) This total charge before decay = total charge offer decay Hence there is a charge conservation in this process. (6) why the final product is helium atom? sine nuckons of fritian nucleus contains one proton. and 2 neutrons. During B-decay neveron decays to a proton with ejection of one eleton (& antineatrire) Thus after ß decay, the nucker will now contain 2porotors & a neatron which is Helium nucleus. Nok that all neutrons (in this case, 2 neutrone) nover can decay us order to maintain the nucleas stability. only those neutrons decays which are excess ccompared with the number of protors (o r= lsx 1015 m, v 8. During B-decay poress, when è is created inside the nucleus, it cannot stay inside of it due to the Heisenberg's uncertainty relation alich states that ax op t e an uncertainty in distance is op; uncertainty in measurmeet of momentum of particle

LLIURETIRO CULTURE in onsor: Radius of nudeas. this op case, mo rx mo for minimum speed - - » - 6.6481094 200 m 4X7 X 1.5 110 15x5.0 18x1027 = 0o7 x 10² m/s ~ 7x 100 m/s. He = (2x1.007276+ 1 x 1,008665 )* 1.66 810-27 17 = 5.018 x 1027