Q 12-12-072JEE MainJEE Main 2023 (12 Apr, Shift 1)Medium
A $12.5\ \text{eV}$ electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be
Answer: (D) 3
From $n=1$: to $n=3$ needs $12.09\ \text{eV}$ (possible), to $n=4$ needs $12.75\ \text{eV}$ (not possible). From $n=3$ the lines are $3\to2$, $3\to1$, $2\to1$: three lines.
Solution by Sreeraj P, M.Sc Physics