Additional Questions nswer the following questions in stand-alone paragraph form

Question

Additional Questions nswer the following questions in stand-alone paragraph formats. Answer each question in a different aragraph One thing that distinguishes different light sources is the width of the observed lines. Which type of light source (atomic, LED, incandescent) gave spectra with the sharpest peaks? With the broadest bands? Which do you think would be a more energy efficient source of red light, a red LED or a white light with a red filter? Explain your answer. Based on the spectrum observed for the fluorescent light, does it contain a hydrogen or a mercury lamp? Does the image on the right support your answer? 1. 2. 3.

Explanation / Answer

1.Incandescent light source produces sharpest spectra and LED produces broadest spectra.An incandescent light bulb contains a tungsten filament that is resistively heated when a current is conducted through it. At temperatures around 2000 K, the filament starts to emit visible light. To prevent the tungsten wire from burning up, the bulb is filled with a gas, usually argon. The heat generated in the filament is transported to the surroundings through radiation, convection, and conduction. An incandescent bulb emits a greater proportion of red light than natural daylight. Emission even extends into the infrared part of the electromagnetic spectrum, which wastes energy and reduces the overall efficiency of the bulb.

LEDs are so much more efficient than incandescent bulbs because they function in a very different way. LEDs are semiconductor devices that emit light when electrons in the conduction band transition across the bandgap via radiative recombination with holes in the valence band. Unlike incandescent bulbs, LEDs emit light over a very narrow range of wavelengths.

2.REd LED is more efficient than white light with red filter.LEDs are so much more efficient than incandescent bulbs because they function in a very different way. LEDs are semiconductor devices that emit light when electrons in the conduction band transition across the bandgap via radiative recombination with holes in the valence band. Unlike incandescent bulbs, LEDs emit light over a very narrow range of wavelengths.

3.A fluorescent lamp typically consists of a long, glass tube containing a low-pressure mixture of mercury and a rare gas, such as argon. Inside of this tube, a nonequilibrium discharge is produced (a plasma). This means that the electron temperature is different from the temperature of the surrounding gas mixture. For example, the electron temperature can be on the order of over 20,000 K, but the gas temperature stays relatively close to room temperature, 300 K. Since the plasma is not in equilibrium, the electron impact reactions modify the chemical composition of the gas mixture in a manner governed by the collisional processes. These collisions can produce electronically excited neutrals, which can subsequently produce spontaneous emission of photons at specific wavelengths.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.