Explain the effect of temperature on the resistivity of conducting materials.
The resistance of most metals rises with rise of temperature whereas that of semiconductors and electrolytes reduces along with increase of temperature. Various metals have vanishing resistivity at absolute zero of temperature. This phenomenon is termed as superconductivity. The resistance of a conductor changes along with temperature according to the law Rt = RO (1 + α t). Here Rt and RO are the resistances at "t" and zero degrees centigrade and α the temperature coefficient of resistance.