Question

For diatomic gas, find the ratio $Q : \Delta U : W$ for isobaric process :-

• A. 2 : 5 : 7
• B. 2 : 3 : 5
• C. 2 : 7 : 3
• D. 7 : 5 : 2

Answer 1

The Correct Option is D

Step 1: Identify molar heat capacities for diatomic gas ($f=5$).
$C_V = \frac{5}{2}R$, $C_P = \frac{7}{2}R$.

Step 2: Write expressions for an isobaric process.
$Q = n C_P \Delta T = \frac{7}{2} n R \Delta T$.
$\Delta U = n C_V \Delta T = \frac{5}{2} n R \Delta T$.
$W = P \Delta V = n R \Delta T$.

Step 3: Find the ratio $Q : \Delta U : W$.
$\frac{7}{2} : \frac{5}{2} : 1 = 7 : 5 : 2$.

Final Answer: Option (4).