What is the most commonly used substance in fluorescent tubes?
(1) Sodium oxide and argon
(2) Sodium vapor and neon
(3) Mercury vapor and argon
(4) Mercury oxide and neon
Answer: (3) A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. It contains mercury vapor and argon. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp.
