Question

Humans can see 400 to 700 nm. Since wavelength changes with medium, will they see the same frequencies corresponding the wavelengths 400 nm to 700 nm from the previous medium or that same wavelengths, that 400nm to 700 nm, but different frequencies?

Answer 1

The wavelength of light changes when it travels through different mediums, but the frequency remains the same. This phenomenon is known as the wavelength-dependent refractive index of a medium.

When light passes through a medium, such as air, water, or glass, its speed changes, and as a result, its wavelength also changes according to Snell's law. However, the frequency of the light remains constant because it is a property of the light itself and is not affected by the medium.

In the case of human vision, our eyes are sensitive to the frequency of light rather than its wavelength. The visible spectrum for humans ranges from approximately 400 to 700 nanometers (nm), corresponding to the range of frequencies that our eyes can detect as different colors. Even though the wavelengths of the light within this range may change when passing through different mediums, the frequencies of the light remain the same.

So, regardless of the medium through which the light travels, humans will perceive the same frequencies corresponding to the range of 400 nm to 700 nm as the same colors, such as violet, blue, green, yellow, orange, and red.