r ~ 10–2 – 10–8 W m
s ~ 102 – 108 S m–1
(ii) Semiconductors: They have resistivity or conductivity intermediate
to metals and insulators r ~ 10–5 – 106 W m
s ~ 105 – 10–6 S m–1
(iii)Insulators: They have high resistivity (or low conductivity) r ~ 1011 – 1019 W m
s ~ 10–11 – 10–19 S m–1
The values of r and s given above are indicative of magnitude and
could well go outside the ranges as well Relative values of the resistivity
are not the only criteria for distinguishing metals, insulators and
semiconductors from each other