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.
Megan is in charge of deciding what type of lights to use for recently installed street lights in a newly built subdivision. To help her in her decision, she asked the residents of the subdivision to vote on whether they would prefer lights that emitted a bluish light or a yellowish light.
If the residents vote on the yellowish lights, should Megan choose the sodium vapor lights or mercury vapor lights for the street lights?