Question 73: Thermodynamics & KTG

Question

If heat engine is filled at temperature 27$^\circ$C and heat of 100 k cal is taken from source at temperature 677$^\circ$C. Work done (in J) is

Accepted Answer

Given,
$\begin{aligned}
& T_2=27^{\circ} \mathrm{C}=300 \mathrm{~K} \
& T_1=677^{\circ} \mathrm{C}=950 \mathrm{~K} \
& \eta=\frac{W}{Q_1}=\frac{Q_1-Q_2}{Q_1} \
& =1-\frac{Q_2}{Q_1}=1-\frac{T_2}{T_1} \
& 	herefore \quad \eta=1-\frac{300}{950}=\frac{13}{19} \
& 	herefore \quad W=\eta Q_1=100 	imes 10^3 	imes \frac{13}{19} \mathrm{cal} \
\end{aligned}$
Also, $4.2 \mathrm{~J}=1 ~\mathrm{cal}$
$\begin{array}{ll}
	herefore & W=100 	imes 10^3 	imes \frac{13}{19} 	imes 4.2 \
\Rightarrow & W=2.87 	imes 10^5=0.28 	imes 10^6 \mathrm{~J}
\end{array}
$

Answer

$0.28	imes10^6$

Answer

$2.8	imes10^6$

Answer

$28	imes10^6$

Answer

$0.028	imes10^6$

Thermodynamics & KTG

If heat engine is filled at temperature 27^\circC and heat of 100 k cal is taken from source at temperature 677^\circC. Work done (in J) is

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