Consider a system made up of 5 sub-systems A, B, C, D, and E that are in thermal contact with each
other and isolated from the surroundings. The sub-systems were all initially at different
temperatures, but after a redistribution of heat among these sub-systems, thermal equilibrium was
established and all sub-systems had the same temperature. The following is a description of the
heat flow with respect to sub-systems A, B, C and D:
Sub-system A lost 5 kJ of heat
Sub-system B gained 9 kJ of heat
Sub-system C lost 2 kJ of heat
Sub-system D gained 6 kJ of heat
What happened to sub-system E?
gained 8
of heat