Question

When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas is

• A. 2/5
• B. 3/5
• C. 3/7
• D. 5/7

Answer 1

The correct option is D

5/7

$f=\frac{\Delta U}{Q}=\frac{n{C}_v\Delta T}{n{C}_p\Delta T}=\frac{C_v}{C_p}=\frac{\frac{5}{2}R}{\frac{7}{2}R}=\frac{5}{7}$