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NEET-XII-Physics

11: Dual Nature Of Radiation And Matter

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Qstn# 13 Prvs-QstnNext-Qstn
  • #13
    What is the
    (a) momentum,
    (b) speed, and
    (c) de Broglie wavelength of an electron with kinetic energy of 120 eV.
    Ans : Kinetic energy of the electron, Ek = 120 eV

    Planck’s constant, h = 6.6 × 10-34 Js

    Mass of an electron, m = 9.1 × 10-31 kg

    Charge on an electron, e = 1.6 × 10-19 C
    (a) For the electron, we can write the relation for kinetic energy as:



    Where,

    v = Speed of the electron



    Momentum of the electron, p = mv

    = 9.1 × 10-31 × 6.496 × 106

    = 5.91 × 10-24 kg m s-1

    Therefore, the momentum of the electron is 5.91 × 10-24 kg m s-1.
    (b) Speed of the electron, v = 6.496 × 106 m/s
    (c) De Broglie wavelength of an electron having a momentum p, is given as:



    Therefore, the de Broglie wavelength of the electron is 0.112 nm.
  • #13-a
    momentum,
    Ans : For the electron, we can write the relation for kinetic energy as:



    Where,

    v = Speed of the electron



    Momentum of the electron, p = mv

    = 9.1 × 10-31 × 6.496 × 106

    = 5.91 × 10-24 kg m s-1

    Therefore, the momentum of the electron is 5.91 × 10-24 kg m s-1.
  • #13-b
    speed, and
    Ans : Speed of the electron, v = 6.496 × 106 m/s
  • #13-c
    de Broglie wavelength of an electron with kinetic energy of 120 eV.
    Ans : De Broglie wavelength of an electron having a momentum p, is given as:



    Therefore, the de Broglie wavelength of the electron is 0.112 nm.