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.
Consider the following text:
Joe walks into his house to see that his son has replaced the light bulbs in both the kitchen and the bathroom. The kitchen is now glowing blue because of the light bulb, and the bathroom has a yellow tint to it. Joe decides he needs to find his son to figure out what type of light bulbs these are and why he chose them.

Which room has a light bulb filled with mercury vapor?