Question

Minimum excitation potential of Bohr's first orbit in hydrogen atom is

• A. $13.6\text{V}$
• B. $3.4\text{V}$
• C. $10.2\text{V}$
• D. $3.6\text{V}$

Answer 1

The correct option is C $10.2\text{V}$

$\text{Excitation potential (V)}=\frac{\text{Excitation energy}}{e}$

The Energy of the $n^{th}$ state of a hydrogen atom,

$E_n=-\frac{13.6\text{eV}}{n^2}$

Minimum excitation energy of first orbit corresponds to excitation from $n=1$ to $n=2$

$\Rightarrow E_1=-13.6\text{eV},E_2=-3.4\text{eV}$

$\therefore$ Minimum excitation energy of first orbit of hydrogen-atom is,

$E_{ex}=E_2-E_1$

$E_{ex}=-3.4-(-13.6)=+10.2\text{eV}$

$\Rightarrow V=\frac{10.2\text{eV}}{e}=10.2\text{V}$

Hence, option $\left(C\right)$ is correct.

Why this question? This question gives a basic idea of excitation potential and excitation energy.