AIIMS 2019 Physics Bohr's Model MCQ Question

For the radius of an electron in the first excited state of Be³⁺ to equal that of a hydrogen atom, we set the equation $r = r_0 \left( \frac{n^2}{Z} \right)$ equal to $r_0$. This leads to $n^2 = Z$, where $Z$ for Be³⁺ is 4, giving $n = \sqrt{4} = 2$. Options B (3), C (4), and D (5) are incorrect because they do not satisfy the condition $n^2 = Z$ for the first excited state of Be³⁺, which specifically requires $n = 2$.