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Why conductivity of conductor decreases while of semiconductor increases with increasing temperature? |
| Answer» Solution :Conductivity of a material depend on two factors Factor 1: no. of electron in conduction BAND Factor 2: COLLISION of conduction electron with core atom Factor 1 INCREASES conductivity and Factor 2 decreases. Increase in temperature causes both factor to increases. For conductor factor 2 dominates over factor 1because conduction and valence band overlapso all the ELECTRONS of valence and are ALREADY in conduction and hence there is no increase in conduction electron with temperature but collision rate of conduction electron with core atom increases resistance. For semiconductor factor 1 dominates over factor 2 As temperature increases electrons from valance band jump to conduction band. Hence, no. of electron in conduction band increases and conductivity increases | |