Chuck asked:


A double-paned window consists of two 60.0 cm × 100 cm glass panes, 2.00 mm thick, separated by a 1.50 cm layer of still air. 25.0 W of heat flow through the window.
What is the temperature difference between the indoors and outdoors? The thermal conductivity of glass is and that of air is

A) 27.6 K
B) 27.3 K
C) 26.9 K
D) 26.7 K
E) 26.3 K

can someone help me with this? it’s a practice problem i can’t get.

spearofheaven asked:


Consider a double-paned window consisting of two panes of glass, each with a thickness of 0.500 cm and an area of 0.825 m^2, separated by a layer of air with a thickness of 1.40 cm. The temperature on one side of the window is 0.00°C; the temperature on the other side is 20.0°C. In addition, note that the thermal conductivity of glass is roughly 36 times greater than that of air.

(a) Approximate the heat transfer through this window by ignoring the glass. That is, calculate the heat flow per second through the 1.40 cm of air with a temperature difference of 20.0 C°. (The exact result for the complete window is 27.0 J/s.) Express your answer with three significant digits.
_____J/s

(b) Use the approximate heat flow found in part (a) to find an approximate temperature difference across each pane of glass. (The exact result is 0.195 C°.) Express your answer with three significant digits.
_____C°
lzzy– Don’t assume people who ask homework questions on here are being lazy. My teacher sucks at explaining all of this material (the book isn’t much help either) and there are some really smart people on here that I have learned a lot from. And unlike you, I remember my coursework long after the semester has passed!

Carly