Vapor lamps are a type of electric light that uses vaporized gas to produce illumination. They typically contain a small amount of metal, such as sodium or mercury, which vaporizes when electricity passes through it. This process creates a bright light that is often used for street lighting, industrial applications, and large outdoor areas. There are two main types of vapor lamps: sodium vapor lamps and mercury vapor lamps. Sodium vapor lamps emit a warm yellow light, while mercury vapor lamps produce a bluish-white light. Both types are known for their energy efficiency and long lifespan compared to traditional incandescent bulbs.