COMEDK 2025 Evening Solved Paper

Concept:The Bohr model applies only to one-electron (hydrogen-like) atoms and introduces quantised angular momentum for the electron.Explanation:Statement A is false. The Bohr model predicts discrete line spectra, not continuous spectra.Statement B is true. Bohr's model postulates that the angular momentum $mvr$ of an electron is quantised as $mvr = n\hbar$, where $n = 1, 2, 3, \dots$.Statement C is false. Singly ionised neon ($\mathrm{Ne}^{+}$) has 9 electrons, so it is not a hydrogen-like atom; the Bohr model does not apply to it. Hence its emission spectrum is not the same as that of hydrogen (1 electron).Statement D is false. $\mathrm{Ne}^{+}$ (9 electrons) is not hydrogen-like, while $\mathrm{He}^{+}$ (1 electron) is hydrogen-like. Their spectra are different; the Bohr model cannot predict the same spectrum for both.Thus, only statement B is correct.Answer:Option B