ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2023

Which of the following atoms/ions have a ground state energy of -54.4 eV ?

  1. A Hydrogen atom
  2. B Deuterium atom
  3. C Singly-ionised helium
  4. D Doubly-ionised lithium
Verified Solution

Answer & Solution

Correct Answer

(C) Singly-ionised helium

Step-by-step Solution

Detailed explanation

\(E_n = -13.6 \frac{Z^2}{n^2} \text{ eV}\) \(-54.4 = -13.6 \frac{Z^2}{1^2}\) \(Z^2 = \frac{-54.4}{-13.6} = 4\) \(Z = 2\) An atom/ion with \(Z=2\) is Singly-ionised helium.