Astronomers recently detected light emitted by a supernova that was originally observed in 1572, just reaching earth now. this light was reflected off a dust cloud; astronomers call such a reflected light a “light echo” (just like reflected sound is called an echo). how would you expect the spectrum of the light echo to compare to that of the original supernova?

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?