Question

The ionisation energy for the H atom is 13.6 eV then the requried energy in eV to excite it from the ground state to next higher state will be (in eV) :

• A. 3.4
• B. 10.2
• C. 12.1
• D. 1.5

Answer 1

Answer: (B)

10.2

For H atom, the energy is inversely proportional to $n^2$.
$\frac{E_2}{E_1}=({\frac{n_1}{n}}_2{)}^2$
$\frac{E_2}{13.6}=(\frac{1}{2}{)}^2$
$E_2=3.4eV$
$\Delta E=E_2-E_1=13.6-3.4=10.2eV$