Which range of electromagnetic waves can humans detect with their eyes?

Which range of electromagnetic waves can humans detect with their eyes?

• A. Visible light
• B. Infrared radiation
• C. Ultraviolet radiation
• D. Microwaves

Answer: (A)

Humans see only a small portion of the electromagnetic spectrum because the eye’s photoreceptors are tuned to that range. The retina has rods and cones that respond to photons in roughly 380–750 nanometers, which we call visible light. When these photons are absorbed, chemical changes in the photopigments trigger nerve signals to the brain, letting us perceive brightness, shapes, and colors. Wavelengths outside this range aren’t detected by the eyes: infrared is felt as heat but not seen, ultraviolet is invisible and can be harmful, and microwaves are not visible at all. So the light we can detect with our eyes is the visible light range.

Humans see only a small portion of the electromagnetic spectrum because the eye’s photoreceptors are tuned to that range. The retina has rods and cones that respond to photons in roughly 380–750 nanometers, which we call visible light. When these photons are absorbed, chemical changes in the photopigments trigger nerve signals to the brain, letting us perceive brightness, shapes, and colors.

Wavelengths outside this range aren’t detected by the eyes: infrared is felt as heat but not seen, ultraviolet is invisible and can be harmful, and microwaves are not visible at all. So the light we can detect with our eyes is the visible light range.