Question

In a hydrogen atom, if energy of an electron in the ground state is 13.6 eV, then that in the 2nd excited state is:

• A. 1.51 eV
• B. 3.4 eV
• C. 6.04 eV
• D. 13..6 eV

Answer 1

The correct option is A 1.51 eV

$2nd$ exited state means $3rd$ energy level or n= 3

$E=13.6z^2/n^2$

So Energy is inversly varies to $n^2$

For H atom, Z is 1

So, $E_3=\frac{13.6}{3^2}eV$

$E_3=\frac{13.6}{9}eV$

$=1.51$ $eV$

Thus, the correct option is $A$