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Q & A: Spectrum of sunlght

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Most recent answer: 06/25/2016
Q:
hi,my question is that[1] how can the sun a single source of light emit a light of seven different wavelengths? why not a single wavelength light? [2]what is a subwavelength?note: i wanted to suggest that the homepage should be regularly updated. the questions in the recent posts stay there for many days which is irritating cause each time i open the home page sme questions are there for days. so all i wanted to suggest that change them regularly.so that many questions will be available in short period of time. thats all. sry, if this is irritating. good luck and keep up.
- ashish deokar (age 17)
pune city, INDIA
A:

The Sun gives off light with a continuous spectrum of wavelengths, all through the microwave, infrared, visible, and ultraviolet ranges. That's more than 7 wavelengths. In fact, it's an uncountable infinity of different wavelengths. 

The light that reaches us generally travels without interruption from the surface of the Sun, a region with a temperature of roughly 5000K. Any black-body (somthing that's good at absorbing and emitting all different wavelengths) at that temperature gives off the same spectrum of light, meaning the same mixture of different wavelengths.  The range is limited at the short-wavelength end by the quantum nature of light. 5000K does not often provide enough energy to give off a high-frequency, high-energy light quantum (photon).

Why is the Sun's surface good at emitting and absorbing all those wavelengths? It's hot enough to make most of the hydrogen atoms fall apart into electrons and protons. Those electrically charged particles respond to electromagnetic waves (light) easily.

Mike W.

p.s. We're in the process of redesigning the site. One change will be to make it easier to scroll through many new-ish answers.


(published on 06/25/2016)

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