Glass has more than three times larger thermal conductivity than air. Yet glass-wool (glass fibers and air) is preferable to insulate wall spaces rather than leaving "empty" air spaces
Why is glass-wool better although glass has larger conductivity than air?
Convection is very important, and the glass fibers reduce the convecting air currents.
You might also like to view...
A 50-cm wire placed in an east-west direction is moved horizontally to the north with a speed of 2.0 m/s
The horizontal component of the earth's magnetic field at that location is 25 ?T toward the north and the vertical component is 50?T downward. What is the emf induced between the ends of the wire? A) 10 µV B) 20 µV C) 30 µV D) 40 µV E) 50 µV
Four identical 1.5-mF capacitors are connected together electrically. What is the least possible capacitance of the combination?
a. 3.0E–4 F b. 2.5E–4 F c. 3.8E–4 F d. 1.5E–3 F e. 6.7E–4 F
A 140. KeV photon strikes an electron and scatters through an angle of 120.°
(a) What is the wavelength of the photon before scattering? (b) What is the photon wavelength after scattering?
Inside a house, stepping on a tile floor barefooted may feel almost cold, but stepping on carpet in an adjacent room feels comfortably warm. Why is this?
a. It's because the tile is below room temperature while the carpet is at room temperature. b. It's because the tile is at room temperature while carpet is normally warmer. c. It's because the thermal conductivity of tile is less than that of carpet. d. It's because the thermal conductivity of carpet is less than that of tile.