Efficiency of a heat engine at high temps

[notsam]

Homework Statement

What is the maximum effciency of a heat engine whose operating tempuratures are 550oC and 365oC?

Homework Equations

E=1-Thot/Tcold

The Attempt at a Solution

PLEASE HELP! My thinking is that the effciency is equal two one minus the temperature in the hot resavour divided by the temperature in the cold resavour. Is that correct?

 

[Andrew Mason]

Homework Statement

What is the maximum effciency of a heat engine whose operating tempuratures are 550oC and 365oC?

Homework Equations

E=1-Thot/Tcold

The Attempt at a Solution

PLEASE HELP! My thinking is that the efficiency is equal to one minus the temperature in the hot reservoir divided by the temperature in the cold reservoir. Is that correct?

You have it upside down. If it was Th/Tc you would have negative efficiency which makes no sense. The correct expression for efficiency of a Carnot engine is:

$$\eta = 1 - \frac{T_c}{T_h}$$

AM

 

[notsam]

Ok :) At least I'm somewhat on the right track. THANKS!

 

[notsam]

I use Kelvin correct?

 

[Andrew Mason]

I use Kelvin correct?

Correct.

AM