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NEET-XII-Physics

46: The Nucleus

with Solutions - page 5
Qstn# iv-13 Prvs-QstnNext-Qstn
  • #13
    In the decay 64Cu → 64Ni + e+ + v, the maximum kinetic energy carried by the positron is found to be 0.650 MeV. (a) What is the energy of the neutrino which was emitted together with a positron of kinetic energy 0.150 MeV? (b) What is the momentum of this neutrino in kg m s-1?
    Use the formula applicable to a photon. (b) What is the momentum of this neutrino in kg m s-1?
    Use the formula applicable to a photon.
    Ans : Given:
    Maximum kinetic energy of the positron, K = 0.650 MeV (a) Neutrino and positron are emitted simultaneously.
    ∴ Energy of neutrino = 0.650 - Kinetic energy of the given positron
    = 0.650 - 0.150
    = 0.5 MeV = 500 keV (b) Momentum of the neutrino, `` P=\frac{E}{c}``
    Here, E = Energy of neutrino
    c = Speed of light
    `` \Rightarrow P=\frac{500\times 1.6\times {10}^{-19}}{3\times {10}^{8}}\times {10}^{3}``
    `` =2.67\times {10}^{-22}{\,\mathrm{\,Kgms\,}}^{-1}``
    Page No 442: (b) Momentum of the neutrino, `` P=\frac{E}{c}``
    Here, E = Energy of neutrino
    c = Speed of light
    `` \Rightarrow P=\frac{500\times 1.6\times {10}^{-19}}{3\times {10}^{8}}\times {10}^{3}``
    `` =2.67\times {10}^{-22}{\,\mathrm{\,Kgms\,}}^{-1}``
    Page No 442:
  • #13-a
    What is the energy of the neutrino which was emitted together with a positron of kinetic energy 0.150 MeV? (b) What is the momentum of this neutrino in kg m s-1?
    Use the formula applicable to a photon.
    Ans : Neutrino and positron are emitted simultaneously.
    ∴ Energy of neutrino = 0.650 - Kinetic energy of the given positron
    = 0.650 - 0.150
    = 0.5 MeV = 500 keV (b) Momentum of the neutrino, `` P=\frac{E}{c}``
    Here, E = Energy of neutrino
    c = Speed of light
    `` \Rightarrow P=\frac{500\times 1.6\times {10}^{-19}}{3\times {10}^{8}}\times {10}^{3}``
    `` =2.67\times {10}^{-22}{\,\mathrm{\,Kgms\,}}^{-1}``
    Page No 442:
  • #13-b
    What is the momentum of this neutrino in kg m s-1?
    Use the formula applicable to a photon.
    Ans : Momentum of the neutrino, `` P=\frac{E}{c}``
    Here, E = Energy of neutrino
    c = Speed of light
    `` \Rightarrow P=\frac{500\times 1.6\times {10}^{-19}}{3\times {10}^{8}}\times {10}^{3}``
    `` =2.67\times {10}^{-22}{\,\mathrm{\,Kgms\,}}^{-1}``
    Page No 442: