Question

700*.135An inventor claims to have developed a heat engine that receives 700 kJ of heat from a source at 500 K and produces 300 kJ of net work while rejecting the waste heat to a sink at 290 K. Is this a reasonable claim?

Answer 1

Answer:

output work is not possible to have more than 294 kJ value so this is not reasonable claim

Explanation:

As we know that the efficiency of heat engine is given as

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

now we will have

$T_2 = 290 K$

$T_1 = 500 K [tex]

[tex]\eta = 1 - \frac{290}{500}$

$\eta = 0.42$

now we know that efficiency is defined as

$\eta = \frac{Work}{Heat}$

$0.42 = \frac{W}{700}$

$W = 294 kJ$

So output work is not possible to have more than 294 kJ value