Which one of the following graph is correct at constant pressure?

Options

A.
B.
C.
D.

Answer

To determine which graph represents a situation at constant pressure, we can analyze the relationship between volume (V) and temperature (T) based on the ideal gas law, which states:

\[ PV = nRT \]

Where:
- \( P \) = Pressure
- \( V \) = Volume
- \( n \) = Number of moles of gas
- \( R \) = Ideal gas constant
- \( T \) = Temperature

### Step-by-Step Solution:

1. **Understand the Ideal Gas Law**:
The ideal gas law relates pressure, volume, and temperature. For a constant pressure scenario, we can rearrange the equation to show the relationship between volume and temperature:
\[ V \propto T \quad \text{(at constant P)} \]

2. **Analyze the Graphs**:
We need to look for a graph that shows a direct proportionality between volume and temperature. This means if we plot volume (V) against temperature (T), we should see a linear relationship.

3. **Check Option A**:
In option A, the graph plots \( \frac{V}{T} \) on the y-axis against \( \frac{1}{V} \) on the x-axis. If \( \frac{V}{T} \) is constant, it implies that as \( \frac{1}{V} \) changes, \( V \) must adjust in such a way that \( V \) remains proportional to \( T \). Thus, this indicates that pressure is constant.

4. **Conclusion**:
Since option A shows that \( V \) is directly proportional to \( T \) at constant pressure, we conclude that option A is the correct graph representing a constant pressure scenario.

### Final Answer:
The correct graph at constant pressure is **Option A**.

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