Question

Temperature of source is ${330}^{\circ }C$. Temperature of sink is changed in order to increase the efficiency of engine from $\frac{1}{5}$ to $\frac{1}{4}$, by

• A. $30K$
• B. $303K$
• C. $603K$
• D. $60K$

Answer 1

The correct option is A $30K$

$\eta =1-\frac{T_2}{T_1}$

$\frac{1}{5}=1-\frac{T_2}{T_1}$

$\frac{1}{4}=1-\frac{T_2^{\prime }}{T_1}$

$\frac{T_2-T_2^{\prime }}{T_1}=\frac{1}{4}-\frac{1}{5}=\frac{1}{20}$

$△T_2=\frac{1}{20}\times (330+273)=30.15K$

$\therefore \left(a\right)$