Heat Engines and Thermal Processes

Object that supplies or receives thermal energy with essentially not change in temperature.( like water)

Virtually no energy loss

Energy in = Energy out

Q_h= W + Q_c

W=Q_h- Q_c

 $e=\frac{W}{Q_h}$  e is efficiency

or $e=\ \frac{Q_h-Q_c}{Q_h}\$  

do no work

if W=0 then  $\Delta E=Q$  

Change in thermal energy is equal to heat

Work is done

Force exerted by a gas=P(pressure) A(area)

 $W=P\Delta V$  

Change at constant temperature

Constant temp means no change in energy  $\Delta E=0$  

  $\Delta E=Q-W$  therefore Q=W

No change in thermal energy

Q=0 therefore

 $\Delta E=-W$