State the factors on which the resistivity of a material depends.

Explanation

Resistivity of a material depends on (1) nature / type of material. (2) temperature of the material. (3) the pressure exerted on the material at small extent.
Resistivity of metallic substances increases with temperature while resistivity of semi-conductor substances decreases with temperature.
Resistivity of alloys increases very slowly with temperature than in case of metals. In other words one can say that, as resistivity of alloys is 100 times than that of pure metals, it is approximately independent of temperature.
Insulators have practically no free electrons and as such have a very high resistivity, which decreases slowly with rise in temperature.