At absolute zero temperature the conductivities of both the insulators and the semiconductors are zero. At any higher temperature the semiconductor may have some conductivity but for insulator it is zero. Explain why.

Explanation

At absolute zero temperature there is no existence of charge carriers in semiconductors or insulators. So their electrical conductivities are zero.At a temperature higher than absolute zero some electron-hole pairs are generated due to thermal energy and they act as charge carriers in semiconductors. Actually , some electrons or holes of the valence band in n-type and p-type semiconductors respectively can cross the narrow band gap and reach the conduction band. Hence semiconductors possess some eletrical conductivities. But at that temperature no charge charge carriers are generated inside insulators and hence their thermal conductivities remain zero.