What is the energy of an electron in a hydrogen atom in a stationary state corresponding to $n = 2$ ?

  • A
    $-5.45 \times 10^{-19} \text{ J}$
  • B
    $-2.40 \times 10^{-19} \text{ J}$
  • C
    $-4.35 \times 10^{-18} \text{ J}$
  • D
    $-6.70 \times 10^{-19} \text{ J}$

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