Part one of term paper
Black Light. What is it? It is a portion of the Ultra-Violet Spectrum that is invisible to our eyes. We can not distinguish it. However, when this radiation impinges on certain materials visible light is emitted and this is known as "fluorescence." Fluorescence is visible to the human eye, in that it makes an object appear to "glow in t ...

Part two of term paper
... light is allowed to fall upon them. This is called luminescence. In most cases, the wave length of the light radiated is longer than that of the ultra-violet excitation but a few exceptions have been found. The quantum theory attempts to explain this property by contending that a certain outside excitation causes an electron to jump from one orbit to another. It is then in an unstable environment causing it to fall back into its original orbit. This process releases energy, and if it is in the ...