A vapor light also produces visible light by electroluminescence The bulb contains a small amount of solid sodium or mercury as well as a mixture of neon and argon gases. When an electric current passes through the gases, it causes the solid sodium or mercury to change to a gas and emit visible light. Sodium vapor lights, like the streetlight pictured in the Figure below , produce yellowish light. Mercury vapor lights produce bluish light. In addition to lighting city streets, vapor lights are used to light highways and stadiums. The bulbs are very bright and long lasting so they are a good choice for these places.
The local high school built a new stadium and wanted to be able to play night games. They decided to check into vapor lights. Eventually decided on Mercury vapor lights rather than Sodium vapor lights.
What kind of light is works by passing an electric current through gas?