Question

The first excitation potential energy or the minimum energy required to excite the atom from ground state of hydrogen atom is

• A. $13.6eV$
• B. $10.2eV$
• C. $3.4eV$
• D. $1.89eV$

Answer 1

The correct option is B $10.2eV$

Energy of ground state of Hydrogen atom, $E_1=\frac{-13.6}{1^2}=-13.6$ $eV$

Energy of first excited state $(n=2)$ of Hydrogen atom, $E_2=\frac{-13.6}{2^2}=-3.4$ $eV$

Thus first excitation potential energy, $\Delta E=E_2-E_1$

$\therefore$ $\Delta E=-3.4-(-13.6)=10.2$ $eV$