Question

Curved outline of a psychrometric chart represents

• A. 100% relative humidity
• B. 0% relative humidity
• C. Wet bulb temperature
• D. Humid volume

Hint:

Remember that along the curved saturation line (100% RH):
\[ \text{Dry-bulb Temperature} = \text{Wet-bulb Temperature} = \text{Dew-point Temperature} \] This is a common question in agricultural process engineering exams.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A psychrometric chart is a graphical representation of the thermodynamic properties of moist air (mixtures of dry air and water vapor) at a constant atmospheric pressure.

Step 2: Detailed Explanation:
Let us analyze the main geometric boundary of the psychrometric chart:

The horizontal axis of the chart shows the dry-bulb temperature, and the vertical axis shows the humidity ratio (moisture content).

The boundary curve on the left side of the chart is called thesaturation curve.

Along this saturation curve, the air cannot hold any more moisture at that dry-bulb temperature; it is fully saturated.

Full moisture saturation is defined as arelative humidity (RH) of 100%.

On this saturation curve, the dry-bulb temperature, wet-bulb temperature, and dew-point temperature are all equal.

Lines of lower relative humidity (e.g., 80%, 50%, 10%) are curved lines located to the right of this main saturation curve, with 0% relative humidity represented by the horizontal axis itself.
Therefore, the curved outline boundary of the chart represents 100% relative humidity.

Step 3: Final Answer:
The correct option is (A), representing 100% relative humidity.