Acyclical heat engine, operating between temperatures of 450º c and 150º c produces 4.00 mj of work on a heat transfer of 5.00 mj into the engine. how much heat transfer occurs to the environment? (b) what is the efficiency of the engine?

(a) Heat transfer to the environment is: 1 MJ and (b) The efficiency of the engine is: 41.5%

Explanation:

Using the formula that relate heat and work from the thermodynamic theory as: solving to Q_out we get: this is the heat out of the cycle or engine, so it will be heat transfer to the environment. The thermal efficiency of a Carnot cycle gives us: where T_Low is the lowest cycle temperature and T_High the highest, we need to remember that a Carnot cycle depends only on the absolute temperatures, if you remember the convertion of K=°C+273.15 so T_Low=150+273.15=423.15 K and T_High=450+273.15=723.15K and replacing the values in the equation we get:

b. a lightning bug, plug of grass, and a worm