Athermopane window consists of two sheets of glass each 10 mm thick, separated by a layer of stagnant air 6 mm thick. find the percentage reduction in heat loss from this pane as compared to that of a single sheet of glass 10 mm thickness. the temperature drop between inside and outside remains same at 25"c. thermal conductivity of glass is 40 times that of air. a) 86.15% b) 96.15% c) 56.15% d) 76.15%