Question

what is the relationship between a light wave’s properties and what we observe?
the energy of the light wave determines its medium.
the color of the light wave determines its direction.
the amplitude of the light wave determines its brightness.
the frequency of the light wave determines its speed.

Explanation:

• Light wave energy depends on frequency, not the medium; the medium affects light speed, not the other way around.
• Light color is determined by frequency/wavelength, not direction; direction is related to propagation path, not color.
• Wave amplitude corresponds to the intensity of the wave, which we perceive as brightness for light.
• Light speed is determined by the medium it travels through, not its frequency; frequency determines color.

Answer:

C. The amplitude of the light wave determines its brightness.