Question

The ionization potential of the hydrogen atom is 13.6 V.The energy needed to ionize a hydrogen atom which is in its second excited state is about ______.

• A. 3.4 eV
• B. 2.5 eV
• C. 10.2 eV
• D. 13.6 eV

Answer 1

The correct option is A 3.4 eV

Ionisation potential for $H_2=13.6V$
Ionisation energy $E_n=\frac{13.6}{n^2}eV$.
For ground state n = 1
$\therefore E_p=13.6eV$
For 2nd excited state n = 2
$\therefore E_p=\frac{13.6}{2^2}=\frac{13.6}{4}=3.4eV$.