Q12(a). Work and efficiency of the stated cycle
One mole of diatomic ideal gas (γ=1.4) completes: (i) adiabatic expansion against constant 1 bar from 10 to 20 L; (ii) cooling and contraction at constant 1 bar back to 10 L; (iii) constant-volume heating to the initial pressure. Calculate work in each step and engine efficiency. Mention redundant data.
Answer in brief
With work on the gas positive, w₁=-1000 J, w₂=+1000 J, w₃=0. Net work is zero, so the stated cycle has zero efficiency.
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All parts of Question 12
- 12(a) Work and efficiency of the stated cycle15 marks
- 12(b) Symmetric carbon dioxide stretch5 marks