Compare the spectra of mercury and sodium with the spectrum of an interstellar nebula. Most street lights are made from one of two elements—mercury or sodium. Explain why astronomers prefer that cities use sodium street lights instead of mercury street lights.

Select light for the type of wave, adjust the wavelength so that the light is red, and increase the amplitude of the light to the max. then, select the start button at the source location to begin producing the waves. light is a form of electromagnetic wave, containing oscillating electric and magnetic fields. the wave amplitude detector mentioned above shows how the electric field oscillates in time at the location of the probe. the amplitude of the wave at the location of the probe is equal to the maximum electric field measured. how does the amplitude of the wave depend on the distance from the source?