AIIMS 2007
- Exam
- AIIMS
- Year
- 2007
- Subject
- Physics
- Chapter
- Atomic Physics
AIIMS 2007 · Physics · Atomic Physics
What is the energy of (He^ + )electron in first orbit?
What is the energy of (\mathrm{He}^{+})electron in first orbit?
Options
- A(40.8 \mathrm{~eV})
- B(-27.2 \mathrm{~eV})
- C(-54.4 \mathrm{~eV})
- D(-13.6 \mathrm{~eV})
Correct answer
C. (-54.4 \mathrm{~eV})
Step-by-step solution
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})