1

2

Why does fiber glass not shrink as much as a pure plastic on

cooling?A. It has no plastic in itB. Glass shrinks very littleC. It is magic

Tensile Stress

Yield Stress

Reduction in AreaElongation

Annealed

3

Heat Flow

Thermal Conductivity

4

Electrons as a Ideal Gas

and

but

Wiedemann-Franz-Lorentz Law

With quantum treatment

Real values agreeLorenz number in 10^-8 Watt ohm/K^2

Metal 273K 373K

Ag 2.31 2.37

Au 2.35 2.40

Cd 2.42 2.43

Cu 2.23 2.33

Ir 2.49 2.49

5

Moremetals

Mo 2.61 2.79

Pb 2.47 2.56

Pt 2.51 2.60

Sn 2.52 2.49

W 3.04 3.20

Zn 2.31 2.33

The Wiedemann-Franz-Lorentz works because

A. Heat and electrical current are carried by the same objects in many materialsB. On a quantum level, everything is the sameC. The mechanism for impeding heat and electrical currents are the same in many materials