If f is defined as above, then which of the following applies to a feed at dew point ?

ANS:A - f = 1

In many engineering contexts, 𝑓f is often used to represent the ratio of the actual vapor pressure of a gas to the saturation vapor pressure at a given temperature. At the dew point, the air is saturated with moisture, meaning its relative humidity is 100%. This also means that the actual vapor pressure of the gas is equal to the saturation vapor pressure at that temperature. So, at the dew point, 𝑓=1f=1. Therefore, the correct answer is: 𝑓=1f=1.