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

Excitation potential = $=\frac{\text{Excitation energy}}{\text{e}}$
Minimum excitation energy corresponds to excitation from n = 1 to n = 2
$\therefore$ Minimum excitation energy in hydrogen atom = $=-3.4-(-13.6)=+10.2 \mathrm{eV}$
so minimum excitation potential = 10.2 eV.