In an Isothermal change, the change in pressure and volume of a gas can be represented for three different temperature; as :
- A.
- B.
- C.
- D.
Show answer and solution
Correct option: C
Solution
For an isothermal process, PV = nRT = constant, so the P-V curves are rectangular hyperbolas. The key features to identify the correct graph:
1. Higher temperature → higher PV product → the hyperbola for T₃ (highest) lies furthest from the origin, T₁ (lowest) lies closest to the origin.
2. Shape: Each curve must be a rectangular hyperbola (P = nRT/V), curving away from both axes, never touching them.
In option 3, the three isotherms are correctly drawn as rectangular hyperbolas with T₃ > T₂ > T₁ ordering from outermost to innermost — higher temperature isotherms lie farther from the origin since at any given volume, higher T means higher pressure (P = nRT/V).
1. Higher temperature → higher PV product → the hyperbola for T₃ (highest) lies furthest from the origin, T₁ (lowest) lies closest to the origin.
2. Shape: Each curve must be a rectangular hyperbola (P = nRT/V), curving away from both axes, never touching them.
In option 3, the three isotherms are correctly drawn as rectangular hyperbolas with T₃ > T₂ > T₁ ordering from outermost to innermost — higher temperature isotherms lie farther from the origin since at any given volume, higher T means higher pressure (P = nRT/V).
[JEE Main 2023 · 24 Jan · Shift 2]