Question

In the Bohr series of lines of hydrogen emission spectrum, the third line from the red end corresponds to which one of the following inter orbit jumps of the electron?

• A. $3\to 2$
• B. $5\to 2$
• C. $4\to 1$
• D. $2\to 5$

Answer 1

The correct option is B $5\to 2$

In the emission spectra of Hydrogen atom, series of lines are observed and are named as Lyman, Balmer, Paschen, Brackett and Pfund depending on the final orbit number ($n_1$). Energy of emitted radiation in these series are different and varies from Ultraviolet, visible to Infrared regions of the spectrum. Balmer series cover the Visible region, therefore red line will appear in Balmer series where $n_1=2$. For the third line from red, therefore $n_2=2+3=5$. Hence option (B) $5\to 2$ is the correct answer.