Q. The energy of a hydrogen atom in the ground state is $- 13.6\ eV$. The energy of a $He^{+}$ ion in the first excited state will be
A) $- 6.8\ eV$
B) $- 13.6\ eV$
C) $- 27.2\ eV$
D) $- 54.4\ eV$
Explanation
(b) $E_{n} = - 13.6\left( \frac{z^{2}}{n^{2}} \right) = - 13.6\left( \frac{4}{4} \right) = - 13.6eV$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.