Question Bank • QB_FP_009 NAT • 2 Marks

Section 3: Farm Power

Farm Power

Subtopic: I.C. engine cycles

Question Statement:

An ideal air-standard Otto cycle operates with a volumetric compression ratio $r = 8.0$. Assuming the adiabatic index $\gamma = 1.40$, the theoretical thermal efficiency of the cycle expressed in percentage is ________ (round off to 1 decimal place).

Answer Key:

56.5

Step-by-Step Solution & Explanation

Thermal efficiency of an air-standard Otto cycle is given by: $\eta_{\text{Otto}} = 1 - \frac{1}{r^{\gamma - 1}}$ Given $r = 8.0$ and $\gamma = 1.40$: $\gamma - 1 = 0.40$ $r^{0.40} = 8^{0.40} \approx 2.2974$ $\eta_{\text{Otto}} = 1 - \frac{1}{2.2974} = 1 - 0.43527 = 0.56473 = 56.47\% \approx 56.5\%$
← Previous (QB_EXP_FP_002) Next (QB_FP_114) →

Practice In Authentic CBT Exam Interface

Test your skills under authentic timed conditions with live scoring and AIR percentile ranking.

Launch CBT Mock Test