Question

The ionization energy of hydrogen atom is $13.6eV$. Hydrogen atoms in the ground state are excited by electromagnetic radiation of energy $12.1eV$. How many spectral lines will be emitted by the hydrogen atoms?

• A. one
• B. two
• C. three
• D. four

Answer 1

The correct option is C three

Energy of electron in hydrogen atom in ground state=-13.5eV.

When a photon of energy of 12.1eV is radiated on atom, the energy gained by the electron is given by :

$E=(-13.6)+12.1=(-1.5)eV$

And we know that energy of an excited electron is given by,

$E=\frac{-13.6}{n^2}(n:numberoforbit)$

$\Rightarrow -1.5=\frac{-13.6}{n^2}\Rightarrow n=3$

Therefore, when a photon of 12.6eV is radiated electron jump to 3 orbit.