Line sources for both UV and visible light in spectroscopy include which pair?

Line sources for both UV and visible light in spectroscopy include which pair?

• A. Mercury and Sodium Vapor Lamps
• B. Tungsten Lamp
• C. Hollow Cathode Lamp
• D. Deuterium Lamp

Answer: (A)

Line sources emit specific wavelengths, not a broad continuum, which makes them ideal for calibrating and analyzing spectra. Mercury vapor lamps provide several well-defined emission lines in both the ultraviolet and visible parts of the spectrum (for example around 254 nm in the UV and around 436 nm in the visible). Sodium vapor lamps produce two very strong lines in the visible region near 589 nm. Together, these two sources offer discrete spectral lines across both UV and visible light, making them a classic pair for UV–Vis line sources. Tungsten lamps give a continuous spectrum, so they’re not line sources; deuterium lamps are mainly UV continuum sources; hollow cathode lamps do emit lines, but their lines depend on the cathode element and aren’t as broadly representative for UV–Vis as the mercury-sodium combination.

Line sources emit specific wavelengths, not a broad continuum, which makes them ideal for calibrating and analyzing spectra. Mercury vapor lamps provide several well-defined emission lines in both the ultraviolet and visible parts of the spectrum (for example around 254 nm in the UV and around 436 nm in the visible). Sodium vapor lamps produce two very strong lines in the visible region near 589 nm. Together, these two sources offer discrete spectral lines across both UV and visible light, making them a classic pair for UV–Vis line sources. Tungsten lamps give a continuous spectrum, so they’re not line sources; deuterium lamps are mainly UV continuum sources; hollow cathode lamps do emit lines, but their lines depend on the cathode element and aren’t as broadly representative for UV–Vis as the mercury-sodium combination.