Q123 / 170 · Manipal (MET) 2016 · Physics

The ionisation potential of hydrogen atom is 13.6 eV . How much energy need to be supplied to ionise the hydrogen atom in the first excited state?

  • A
    13.6 eV
  • B
    27.2 eV
  • Correct answer
    C
    3.4 eV
  • D
    6.8 eV

Solution

Ionisation energy of nth state $=-E_n$ For the first excited state, $n=2$ and energy in that state is, $\frac{13.6}{2^2} \mathrm{eV}=\frac{13.6}{4} \mathrm{eV}$ $=3.4 \mathrm{eV}$

Hence, the correct answer is option: 'C'.

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