Final answer:
High-pressure sodium lamps are a type of lighting commonly used in outdoor security lighting. They contain sodium vapor and produce a yellowish light. They are known for their high efficiency and long lifespan.
Step-by-step explanation:
High-pressure sodium lamps are a type of lighting commonly used in outdoor security lighting. They contain sodium vapor and produce a yellowish light. The light is produced when the sodium vapors are excited by an electric current, causing the release of energy in the form of visible light.
These lamps have a characteristic emission spectrum in the range of 350-700 nm, with a broadening of the spectral lines due to collisions. They are known for their high efficiency and long lifespan, making them suitable for outdoor lighting applications.
In addition to security lighting, high-pressure sodium lamps are also used in street lighting and industrial lighting due to their energy efficiency.