The output of most fluorescent lights is weighted toward

• A. Red and orange
• B. Purple and violet
• C. Yellow and brown
• D. Blue and green

Answer: (D)

The light from fluorescent lamps is produced by exciting a phosphor coating with ultraviolet energy from mercury vapor, and the phosphors then emit visible light. The specific phosphor blends used for general lighting are designed to give white light, but they tend to emit more strongly in the blue and green portions of the spectrum than in red or orange. This makes the lamp’s spectrum weighted toward blue and green, which is why these lamps often look cooler or bluish. Red-orange components are relatively weak, and purple or violet aren’t dominant in normal fluorescent light.