MCQ
A $15.0\, eV$ photon collides with and ionizes a hydrogen atom. If the atom was originally in the ground state (ionization potential $=13.6\, eV$), what is the kinetic energy of the ejected electron? .......... $eV$
  • $1.4$
  • B
    $13.6$
  • C
    $15$
  • D
    $28.6$

Answer

Correct option: A.
$1.4$
a
Conservation of energy requires that the $15.0\, eV$ photon energy first provides the
ionization energy to unbind the electron, and then allows any excess energy to become the electron’s kinetic energy. The kinetic energy in this case is $15.0\, eV -13.6\, eV = 1.4\, eV.$

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