Chapter 31, Problem 9TE

To determine

The reason for the fog up of sunglasses during a summer when leave out from an air-conditioned room.

Answer to Problem 9TE

The temperature at the surface of the sunglasses decreases because of the air conditioner in the room. When a person moves outside the air-conditioned room, the cold sunglasses came in contact with the hot air outside. The water vapor droplet available on the glass surface cools down and condenses.

Explanation of Solution

Whenever a person moves between various environments where the dew point is met, glasses will fog up. The dew point is the temperature at which the air gets soaked with water vapor and differs from air pressure.

At the point when the temperature falls beneath this point, dampness noticeable all around gathers and causes the formation of mist on your glasses. This condition will emerge additionally going from a freezing domain a lot hotter one. This condition may not happen if the relative stickiness is low, so there is inadequate water vapor to condense into water.

Conclusion:

Therefore, the temperature at the surface of the sunglasses decreases because of the air conditioner in the room. When a person moves outside the air-conditioned room, the cold sunglasses came in contact with the hot air outside. The water vapor droplet available on the glass surface cools down and condenses.