Calculating Heat Engine Efficiency: What is the Energy Input?

[kirsten_2009]

Homework Statement

[/B]
Suppose you build a steam engine that exhausted 1000 J of thermal energy while performing 300 J of work. What is the energy input? What is the efficiency?

Homework Equations

The Attempt at a Solution

Would this be correct?


Thermal E Input = work + exhaust = 300 J + 1000 J = 1,300 J




Efficiency = work output / thermal energy input = 300 J / 1,300 J = 0.231 J

 

[nasu]

The efficiency does not have units of Joules. It does not have any units, it's a ratio.

 

[kirsten_2009]

The efficiency does not have units of Joules. It does not have any units, it's a ratio.

Thanks!