Question

An ideal gas heat engine operates in a Carnot cycle between $127^\circ C$ and $227^\circ C$ . It absorbs $6kcal$ at the higher temperature. The amount of heat (in $kcal$ ) converted into work is equal to

• A. $3.5$
• B. $1.6$
• C. $1.2$
• D. $4.8$

Answer 1

Answer: (C)

Efficiency of a carnot engine is given by $\eta=1-\frac{T_{2}}{T_{1}}$
or $\frac{W}{Q}=1-\frac{T_{2}}{T_{1}}\Rightarrow \frac{W}{6}=1-\frac{\left(\right. 273 + 127 \left.\right)}{\left(\right. 273 + 227 \left.\right)}$
$\Rightarrow W=1.2kcal$