Question

In a psychrometric chart, one axis represents dry-bulb temperature. The axis that is perpendicular to the dry-bulb temperature axis represents:

• A. wet-bulb temperature
• B. specific humidity
• C. relative humidity
• D. enthalpy

Hint:

In psychrometric charts, the dry-bulb temperature is typically plotted on the horizontal axis, and specific humidity is plotted on the vertical axis.

Answer 1

The Correct Option is B

Step 1: Understanding a Psychrometric Chart
A psychrometric chart is a graphical representation of the thermodynamic properties of moist air. It shows the relationship between the dry-bulb temperature, the wet-bulb temperature, the specific humidity, the relative humidity, and other thermodynamic properties of air.

Step 2: Dry-Bulb Temperature
On a psychrometric chart, the horizontal axis typically represents the dry-bulb temperature, which is simply the temperature of air as measured by a standard thermometer.

Step 3: Perpendicular Axis
The axis that is perpendicular to the dry-bulb temperature axis represents another thermodynamic property of moist air. Based on the options provided, this axis corresponds to specific humidity.

Step 4: Why Specific Humidity?
Specific humidity is the mass of water vapor per unit mass of dry air. In a psychrometric chart, this is typically plotted on the vertical axis, perpendicular to the dry-bulb temperature. Specific humidity increases as we move upward on the chart, indicating that more water vapor is present in the air.

Step 5: Conclusion
Thus, the axis that is perpendicular to the dry-bulb temperature axis in a psychrometric chart represents specific humidity.

Therefore, the correct answer is (B) specific humidity.