ultra voilet rays

[green finger]

we all know they come form the sun but, do they come frm the heat of the sun or the light given off the sun

[heathfield]

Ultra-violet is at the high frequency end of the colour spectrum while infra-red, associated with heat, is at the lower end.

[mibn2cweus]

The energy produced by the Sun is largely a product of the fusion of hydrogen atoms deep within its core. This internally generated energy is in the form of gamma rays which acquire lower energy levels as they are repeatedly absorbed and reemitted as they migrate toward the cooler surface of the Sun, a journey that takes thousands of years to complete. Once at the surface the energy produced within the Sun is free to radiate out into space in the form of light. Photons of light are emitted when electrons settle into a more stable lower energy state within atoms. When a photon of light emitted by the Sun reaches another atom in the Earth's atmosphere or surface that photon's energy excites the atom that it encounters and raises its energy level at the same time annihilating the photon.

Heat is the distribution of energy within or between materials through contact or radiation. Energy seeks an even distribution within a material. When a material with a higher level of energy encounters a material with a lower level of energy some of its energy is absorbed to achieve equilibrium. What we experience as heat is not light but the exchange of energy between atoms or atomic particles as a result of their encounters due to their respective motions.

[Gef]

Heat (infra-red), visible light and ultra-violet are forms of electromagnetic radiation of different wavelengths. They are all emitted by the Sun but we are aware of them in different ways. Infra-red is felt as heat (warmth), Visible light affects our eyes and ultra-violet burns us.