JEE Main & Advanced Chemistry Structure of Atom / परमाणु संरचना Question Bank Self Evaluation Test - Structure of Atom

  • question_answer
    At temperature T, the average kinetic energy of any particle is \[\frac{3}{2}KT.\] The de Broglie wavelength follows the order:

    A) Visible photon > Thermal neutron > Thermal electron

    B) Thermal proton > Thermal electron > Visible photon

    C) Thermal proton > Visible photon > Thermal electron

    D) Visible photon > Thermal electron > Thermal neutron

    Correct Answer: D

    Solution :

    [d] Kinetic energy of any particle \[=\frac{3}{2}KT\] Also \[K.E.=\frac{1}{2}m{{v}^{2}}\] \[\frac{1}{2}m{{v}^{2}}=\frac{3}{2}KT\Rightarrow {{v}^{2}}=\frac{3KT}{m}\] \[v=\sqrt{\frac{3KT}{m}}\] De-broglie wavelength \[=\lambda =\frac{h}{mv}=\frac{h}{m\sqrt{\frac{3KT}{m}}}\] \[\lambda =\frac{h}{\sqrt{3KTm}}\lambda \propto \frac{1}{\sqrt{m}}\] Mass of electron < mass of neutron \[\lambda \](electron) > \[\lambda \] (neutron)


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