Q. The sink temperature of a heat engine $77℃.$ The efficiency is 30%. The source temperature is
A) $500℃$
B) $227℃$
C) $317℃$
D) $427℃$
Explanation
(b) Efficiency of a heat engine
$\eta = 1 - \frac{T_{2}}{T_{1}}$
$or\ \frac{30}{100} = 1 - \frac{77 + 273}{T_{1}}$
$or\ \ \frac{350}{T_{1}} = 1 - \frac{30}{100} = \frac{7}{10}$
$\Rightarrow \ \ \ T_{1} = 500K\ \ \ or\ 227℃$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.