Two layers of 4mm-thick glass, sandwiching a 4mm air gap in between, is used for a window of 2 meters wide and 1 meter tall. You can consider them as three layers. The three layers have the same width, height, and thickness. The thermal energy flowing through each of the three layers are the same every second. The thermal conduction power through one glass layer is the same as that through the air gap. The thermal conductivity of air (0.024 W/mC) is 33.3 times smaller than that of glass (0.80 W/mC). Q8. The actual temperature difference across the air gap is how many times the temperature difference across one layer of the glass now