Answer:
0.544 eV
Explanation:
To ionize the hydrogen atom [tex]n_f\rightarrow infinte[/tex]
So the required energy is [tex]\Delta E=13.6(\frac{1}{n_i^2}-\frac{1}{n_f^2})[/tex] as [tex]n_f\rightarrow infinte[/tex]
So [tex]\Delta E=13.6\frac{1}{n_i^2}[/tex]
We have to calculate the energy required to ionize hydrogen atom when it is in n=5
So the energy should be less than [tex]\Delta E=13.6\frac{1}{5^2}=0.544eV[/tex]