The familiar phenomenon of a rainbow results from the diffraction of sunlight through raindrops. does the wavelength of light increase or decrease as we proceed outward from the innermost band of the rainbow?

The wavelength of light increases.

Explanation:

As we proceed outward from the innermost band of the rainbow the wavelength of light increases.

when light travels through a prism, the wavelengths separate into different colors (which are colors of the rainbow). These colors are Red, Orange, Yellow, Green, Blue, Indigo and Violet. Each color has a different wavelength. Violet has the shortest wavelength of about 380 nanometers and red has the longest of about 700 nanometers. When you look at a rainbow, the innermost portion has a violet coloration while the outer most is red, hence the wavelength of light increases from the innermost band to the outermost. That is, from about 380 nanometers to about 700 nanometers.

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