On a cold night the temperatures of the two surfaces of a glass windowpane in a
ID: 2238911 • Letter: O
Question
On a cold night the temperatures of the two surfaces of a glass windowpane in a house are 7.8Explanation / Answer
sol: as we know that A. (dQ/dt)/A = k1*dT/d = 0.8*0.2/0.00348 = 45.977 W/m^2 B. From the ref, dQ/dt = k2*A*dT ==> k2 = (dQ/dt)/(A*dT) We know (dQ/dt)/A from answer A. To solve for k2 we simply need to divide that by dT, which is 21.8-8 C on the inside and 7.8-0 C on the outside. Inside: k2 = 45.977/13.8 = 3.332 W/m^2-C Outside: k2 = 45.977/7.8 = 5.894 W/m^2-C Note that k2 is a property of the air, not the glass. Typical values for air are quoted in the ref as 10 to 100, so these answers are below the "typical" range. use this
Related Questions
Hire Me For All Your Tutoring Needs
Integrity-first tutoring: clear explanations, guidance, and feedback.
Drop an Email at
drjack9650@gmail.com
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.