Choose the correct alternative:
(a) Alloys of metals usually have (greater/less) resistivity than that of their consituent metals.
(b) Alloys usually have much (lower/higher) temperature coefficients of resistance than pure metals.
The resistivity of the alloy manganin is nearly independent of/increases rapidly with increase of temperature.
The resistivity of a typical insulator (e.g., amber) is greater than that of a metal by a factor of the order `(10^(22) // 10^(23))`.
