What is the wavelength of sunlight?

Answer 1

Sunlight, which for the moment we'll consider to be visible white-colored light, is actually made up of many, many different wavelengths (colors) of light. Yes, a wavelength of light corresponds to its color, and a mixture of all the visible colors of light produces white light.

How do we know? The fact that white light is actually a mixture of colors (and therefore, wavelengths) is demonstrated when we pass white light through a prism. The prism splits the white light into the component colors, which shine in separate bands of color as the light exits the prism.

Blue light is a shorter wavelength, green and yellow are medium wavelengths, and red light is a longer wavelength. Ultraviolet, which is invisible, is very short wavelength light, while infrared, also invisible, is very long wavelength light. Sunlight contains these invisible lights as well as the visible colored lights.

Answer:

The color and wavelength of light that is produced is determined by what element produces it. The sun produces a lot of the group 18 (noble gases) elements so if you want to find the wavelength of sunlight you would have to measure the wavelengths of some of the Noble gases, UV radiation, and other forms of electromagnatic radiation.

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Actually, the second answer given is only partially correct. Light can be produced in a few different ways. If light is produced by changes in electron orbitals within an element (photoelectric effect), as happens in fluorescent lights, LEDs, lasers, or gas lamps etc., then indeed the wavelength of light is determined by the element and is thus restricted to a few discreet values.

However, light can also be produced by 'blackbody radiation'. This is associated with hot objects - incandescent light bulbs, metal glowing when hot, even the infrared light emitted by human bodies. When light is produced in this way, it emits a continuous spectrum, meaning that many different wavelengths are produced, not just a few. The peak (strongest) wavelength will be determined by temperature alone, from an equation called 'Wien's law'.

Both kinds of light are generated by the sun, but the blackbody radiation is much more powerful due to the high temperature of the sun. The surface of the sun is approximately 6000 degrees Kelvin, which means that the peak wavelength emitted by the sun is about 483 nm.

This wavelength is in the middle of the visible range of colors. A coincidence? Not at all! Our eyes have evolved to be most sensitive to the colors that are most generated by the sun.

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