Fig. 2.2 (a) When an endothermic process
occurs in an adiabatic system, the
temperature falls; (b) if the process is
exothermic, the temperature rises.
(c) When an endothermic process occurs
in a diathermic container, energy enters as
heat from the surroundings, and the system
remains at the same temperature. (d) If the
process is exothermic, energy leaves as heat,
and the process is isothermal.