Question

In Mollier chart, an isentropic process is represented by a line.

• A. Horizontal
• B. Vertical
• C. Inclined
• D. Curved

Hint:

Remember: Isentropic = Constant Entropy. Since Entropy is the "X" (bottom) axis of a Mollier chart, staying at the same "X" value means you can only move up or down—which forms a Vertical line.

Answer 1

The Correct Option is B

1. Understanding the Chart Axes:

• Y-Axis (Vertical): Represents Enthalpy ($h$).

• X-Axis (Horizontal): Represents Entropy ($s$).

2. Defining Isentropic Process: An isentropic process is one in which the

Entropy remains constant ($s_1 = s_2$). This is typical of ideal expansions in turbines or ideal compressions in pumps where there is no heat transfer and no internal friction.

3. Representation on the Chart: Because an isentropic process means the value on the X-axis (Entropy) does not change while the value on the Y-axis (Enthalpy) increases or decreases:

• The process must be a straight line moving up or down.

• This creates a perfectly

Vertical line on the chart.
Conversely, a process at constant enthalpy (like throttling) would be represented by a horizontal line.