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
[Solution from source] Eₙ = −13.6 Z²/n² eV. For He⁺, Z = 2 and first excited state n = 2: E = −13.6 × 4/4 = −13.6 eV. −54.4 eV is the He⁺ ground state. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.