Final answer:
The smallest-wavelength line in the Balmer series is the transition from the highest energy level observed (often n=5) to n=2, which is in the visible part of the spectrum as violet light. Transitions from even higher levels start moving into the UV range of the spectrum. The correct option is B.
Step-by-step explanation:
The smallest-wavelength line in the Balmer series corresponds to the highest energy transition to the n=2 level. The Balmer series describes the transitions of electrons from a higher energy level (n > 2) to the second energy level (n=2) in a hydrogen atom. As the energy difference between levels increases, the frequency of the emitted photon also increases, leading to a shorter wavelength.
In the Balmer series, the transition from n=3 to n=2 is known as H-alpha and is visible as red light. The smallest-wavelength line occurs for a transition from infinity to n=2, which means it is the limit of the series in the ultraviolet (UV) part of the spectrum, but for practical purposes, the transition from n=∞ to n=2 is not observed, and instead, we often consider the transition from n=3 to n=2 as the first observable line.
Visible and UV Lines in Balmer Series
- Lines from n=3 to n=2 (H-alpha) and higher up to n=6 to n=2 are visibly observed in the spectrum.
- The line corresponding to the transition from n=7 to n=2 marks the start of the UV part of the Balmer series.
The smallest-wavelength Balmer line that can be observed is actually H-gamma, which results from an electron transitioning from the n=5 level to n=2. This line is still within the visible spectrum and appears as a violet color.