JEE Main Thermodynamics: Cp/Cv Matching Concept 💡
❓ Question Match the following: LIST–I A. Triatomic rigid gas B. Diatomic non-rigid gas C. Monoatomic gas D. Diatomic rigid gas LIST–II C p / C v = 5 / 3 C_p/C_v = 5/3 C p / C v = 7 / 5 C_p/C_v = 7/5 C p / C v = 4 / 3 C_p/C_v = 4/3 C p / C v = 9 / 7 C_p/C_v = 9/7 🖼️ Question Image ✍️ Short Solution This is a pure degrees of freedom question . No formulas to memorize separately — just remember: γ = C p C v = f + 2 f Where f f = degrees of freedom 🔥 🔹 Step 1 — Formula to Remember (MOST IMPORTANT 💯)** For ideal gas: C v = f 2 R C_v = \frac{f}{2}R C p = C v + R = f + 2 2 R C_p = C_v + R = \frac{f+2}{2}R So: γ = f + 2 f \boxed{\gamma = \frac{f+2}{f}} 🔹 Step 2 — Monoatomic Gas Monoatomic gas has: f = 3 f = 3 So: γ = 3 + 2 3 = 5 3 \gamma = \frac{3+2}{3} = \frac{5}{3} ✔️ Matches option 1 So: C → 1 \boxed{C \rightarrow 1} 🔹 Step 3 — Diatomic Rigid Gas Rigid diatomic gas: 3 translational 2 rotational f = 5 f = 5 γ = 5 + 2 5 = 7 5 \g...