Question

Відносна вологість повітря в кабінеті фізики 66 %. За якої температури надворі почнуть запотівати вікна в кабінеті, якщо температура повітря в ньому 20 градусів? Вважайте,що температура скла дорівнює температурі повітря надворі й що кількість водяної пари в приміщенні не змінюється.

Answer 1

1 найдем парциальное давление при 20 грудусов
Ф=P*100%/Pнас         P=Pнас*0,6=2,33*0,6=1,398 кПа
по таблице находим температуру выпадения росы ( точку росы)
Окна запотеют при температуре оконных стекл меньше 12 градусов

Answer 2

Relative Humidity and Window Condensation

The relative humidity of the air in the physics classroom is 66%. You would like to know at what outdoor temperature the windows in the classroom will start to condense if the air temperature inside is 20 degrees Celsius. It is assumed that the temperature of the glass is the same as the outdoor temperature and that the amount of water vapor in the room remains constant.

To determine the outdoor temperature at which the windows will start to condense, we need to consider the dew point temperature. The dew point temperature is the temperature at which the air becomes saturated and condensation begins to form. When the air temperature reaches the dew point temperature, it can no longer hold all the moisture in the form of water vapor, and some of it starts to condense.

To calculate the dew point temperature, we can use the formula:

Dew Point Temperature = Temperature - ((100 - Relative Humidity) / 5)

Let's calculate the dew point temperature using the given relative humidity of 66% and the air temperature of 20 degrees Celsius:

Dew Point Temperature = 20 - ((100 - 66) / 5) = 20 - (34 / 5) = 20 - 6.8 = 13.2 degrees Celsius

Therefore, when the outdoor temperature drops to approximately 13.2 degrees Celsius or lower, the windows in the physics classroom will start to condense [[1]].

Please note that this calculation assumes ideal conditions and does not take into account factors such as insulation, air circulation, or the presence of other sources of moisture in the room.