AP EAMCET Engineering 20 Apr 2019 Shift 2 Paper

A window used to thermally insulate a room from outside consists of two parallel glass sheets each of area 2.6 m2 and thickness 1 cm separated by 5 cm thick stagnant air. In the steady state, the room-glass interface is at 18 °C and the glass-outdoor interface is at - 2 °C. If the thermal conductivities of glass and air are respectively 0.8 Wm−1K−1 and 0.08 Wm−1K−1, the rate of flow of heat through the window is