... the First Law of Thermodynamics interface of the two layers, in 8C, and (b) the rate of heat transfer through the wall, in W per m2 of surface area.2.48 An insulated frame wall of a house has ... devel-opment of this edition. We greatly appreciate their con-tributions:John Abbitt, University of FloridaRalph Aldredge, University of California-DavisLeticia Anaya, University of North TexasKendrick ... the rate of heat transfer.2.60 As shown in Fig. P2.60, the outer surface of a transistor is cooled convectively by a fan-induced flow of air at a temperature of 258C and a pressure of 1 atm....