Question

The temperature and the dew point in an open room are ${20}^0$C and ${10}^0$C. If the room temperature drops to ${15}^0$C, what will be the new dew point ?

Answer 1

Temperature = ${20}^0$ C, dew point = ${10}^0$ C

The place is saturated at ${10}^0$ C even if the temperature drop dew point remains unaffected

The air has the vapour pressure which is the saturation VP at ${10}^0$ C if saturated vapour pressure does not change on temperature.