Choose the only false statement form the following

Options

A. Substance with energy gap of the order of `10 eV` are insulators
B. The conductivity of a semiconductor increases with increases in temperature
C. In conductors the valence and conduction bands may overlap
D. The resistivity of a semiconductor increases with increases in temperature

Answer

A

Explanation

In insulators energy gap is the order of `5` to `10 eV` and it is partically impossible to impart this much amount of energy to the electrons in valence band. So as to jump to conduction band. So, choice (a) is correct. In semiconductor with the rise in temperature more electrons from valence band jump to conduction band and this result in increases in conductivity. So, choice (b) is correct. In conductors, the conduction band is either partially fielld or the conduction band overlap on the valence band. So, choice (c) is correct. In semiconductors, resistivity decreases with increases in temperature. So, choice (d) is wrong.