One process known as a practical form of this process uses an isobaric process for its addition and rejection processes. This process gives an upper limit of efficiency equal to one minus the temperature of the cold reservoir divided by the temperature of the hot reservoir, thus this process gives a quantifiable limit to the second law of thermodynamics. This process sees no change in entropy and contains four steps; the first step is the isothermal expansion of a gas to drive a piston. For 10 points, name this idealistic process that describes the most efficient heat 
One process known as a practical form of this process uses an isobaric process for its addition and rejection processes. This process gives an upper limit of efficiency equal to one minus the temperature of the cold reservoir divided by the temperature of the hot reservoir, thus this process gives a quantifiable limit to the second law of thermodynamics. This process sees no change in entropy and contains four steps; the first step is the isothermal expansion of a gas to drive a piston. For 10 points, name this idealistic process that describes the most efficient heat engine, a non-obtainable process developed by a French physicist.
One process known as a practical form of this process uses an isobaric process for its addition and rejection processes.
{Carnot} cycle