Neon gas in sodium vapor lamp assists in developing enough heat to vaporize the sodium.

1. The lamp contains a small amount of solid sodium metal inside the U-shaped tube.

2. When an electric current is applied, the electrodes at either end of the tube ionize the neon gas, creating a small amount of heat that then vaporizes the sodium metal.

3. As the temperature inside the lamp increases, the sodium metal vaporizes and then ionizes to produce the monochromatic yellow light.

4. The lamp takes several minutes to reach its full light output, as the sodium metal needs time to heat up and vaporize.

5. The yellow light produced by the lamp is monochromatic, meaning it contains only a single wavelength of light. This gives it a distinct color and makes objects appear gray.