Incandescence: The emission of light from a substance, whole atoms are excited by high temperature, is called incandescence. The light from the heated tungsten filament of an incandescent bulb (the common electric bulb) consists of many frequencies and therefore appears white. The sun is also an incandescent source.
Fluorescence: Besides heating or bombarding with fast moving particles, an atom can also be excited by the absorption of photons of light. Many substances undergo excitation when illuminated with photons of ultraviolet light and then emit visible light upon de-excitation. Such substances are called fluorescent substances and the phenomenon is called fluorescence.
Fluorescence: Besides heating or bombarding with fast moving particles, an atom can also be excited by the absorption of photons of light. Many substances undergo excitation when illuminated with photons of ultraviolet light and then emit visible light upon de-excitation. Such substances are called fluorescent substances and the phenomenon is called fluorescence.