Q 12-12-071JEE MainJEE Main 2023 (11 Apr, Shift 2)Easy
The energy of $\text{He}^+$ ion in its first state is (The ground state energy for the Hydrogen atom is $-13.6\ \text{eV}$)
Answer: (C) $-13.6\ \text{eV}$
Here "first state" is taken as the first excited state ($n=2$), as in the official key:
$$E=-13.6\times\frac{Z^2}{n^2}=-13.6\times\frac44=-13.6\ \text{eV}$$
(The ground state of $\text{He}^+$ would be $-54.4\ \text{eV}$.)
Solution by Sreeraj P, M.Sc Physics