At a Particular Point on a PV Diagram,the Magnitude of the Slope

Multiple Choice

At a particular point on a PV diagram,the magnitude of the slope of a curve that represents an adiabatic process is

A) zero.
B) infinite.
C) the same as that of an isotherm through the same point.
D) less than that of an isotherm through the same point.
E) greater than that of an isotherm through the same point.