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Question: Answered & Verified by Expert
What is the energy of \(\mathrm{He}^{+}\)electron in first orbit?
PhysicsAtomic PhysicsAIIMSAIIMS 2007
Options:
  • A \(40.8 \mathrm{~eV}\)
  • B \(-27.2 \mathrm{~eV}\)
  • C \(-54.4 \mathrm{~eV}\)
  • D \(-13.6 \mathrm{~eV}\)
Solution:
1027 Upvotes Verified Answer
The correct answer is: \(-54.4 \mathrm{~eV}\)
For hydrogen like atoms like \(\mathrm{He}^{+}, \mathrm{Li}^{++}\)etc, the energy in an \(n^{\text {th }}\) orbit is given by
\(E_n=\frac{-Z^2 13.6}{n^2} \mathrm{eV}\)
For \(\mathrm{He}^{+}, Z=2\)
\(\therefore \quad E_1=\frac{-(2)^2 13.6}{(1)^2} \mathrm{eV}=-54.4 \mathrm{eV}\)

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