IUPAC recommends
the use of the term resistivity over specific resistance and hence in the
rest of the book we shall use the term resistivity Physically, the resistivity
for a substance is its resistance when it is one metre long and its area
of cross section is one m2 It can be seen that:
1 W m = 100 W cm or 1 W cm = 0 01 W m
The inverse of resistance, R, is called conductance, G, and we have
the relation:
G = 1
R = ρ
A=κ
A
l
l
(2