A low-pressure sodium vapor lamp used in street lighting emits nearly monochromatic…

PHYSICS · Multi-part · CBSE · Physics · Electromagnetic Waves · Electromagnetic Waves

Problem

A low-pressure sodium vapor lamp used in street lighting emits nearly monochromatic yellow light with a wavelength of 589 nm in air. Assume that light in air travels at the same speed it would in a vacuum. Use the following constants as needed: • speed of light in vacuum: 3.00×108 m s−13.00\times10^{8}\,\text{m}\,\text{s}^{-1} • Planck constant: 6.626×10−34 J s6.626\times10^{-34}\,\text{J}\,\text{s} • 1 eV=1.602×10−19 J1\,\text{eV}=1.602\times10^{-19}\,\text{J} (a) Calculate the frequency of the yellow light. (b) Determine the energy, in joules, of a single photon of this yellow light. (c) Express the photon energy calculated in part (b) in electron volts (eV).

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