Final answer:
In the scenario of signaling with a flashlight using Morse code, the flashlight is modulating the light's amplitude, which corresponds to amplitude modulation (AM) of an electromagnetic wave, not frequency modulation (FM). Option 2 is correct.
Step-by-step explanation:
When someone is signaling with a flashlight using Morse code, they are utilizing a form of amplitude modulation (AM) of an electromagnetic (EM) wave. In communications, information can be encoded into EM waves by changing certain properties of the wave.
These properties include the amplitude, frequency, or phase. With amplitude modulation, the amplitude of the wave is varied, while the frequency remains constant. On the other hand, frequency modulation (FM) involves varying the frequency of the carrier wave.
Despite Morse code typically being defined by its temporal pattern of short and long signals (dots and dashes), when using a flashlight, the visible light wave itself can be seen as being modulated in amplitude—bright for a signal and off for no signal, with no change in the frequency of the light.