Question

Which one of the following hypothetical heat engine cycles represents maximum efficiency ?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

$\text{Option-a}$

$W=\text{Area of}\Delta ABC=\frac{1}{2}\times 4\times 400=800kJ$

$Q_s=4\times 800=3200\text{kJ}$

$\eta =\frac{W}{Q}=\frac{800}{3200}=25\text{\%}$

$\text{Option-b}$

$W=800kJ$

$Q=W+400\times 4=800+1600$

$=2400kJ$

$\eta =\frac{w}{Q}=\frac{800}{2400}$

$=33.33\text{\%}$

$\text{Option-c}$

$W=800kJ$

$Q=800\times 4=3200kJ$

$\eta =\frac{800}{2400}=25\text{\%}$

$\text{Option-d}$

$W=800kJ$

$Q=W+\frac{1}{2}\times 4\times (600-400)+400\times 4$

$=800+400+1600+2800kJ$

$\eta =\frac{800}{2800}=28.58\text{\%}$