question_answer

The electrical conductivity of a metal decreases with rise in temperature while that of semi-conductor increases. Justify

Answer:

                The electrical conductivity of a metal decreases with the rise in temperature because the positively charged kernels resent in the electron sea also acquire mobility and obstruct the movement of valence electrons responsible for conductivity. In semi-conductors, the electrical conductivity increases because more electrons are in a position to move from valence band to the conduction band since there is only a small energy gap.