Physics - Semiconductors Question with Solution | TestHub

Insulators are materials that offer very high resistance to the flow of electric current. Their energy band gap is very large (typically greater than $3\text{ eV}$), which means there are almost no free electrons available for conduction at room temperature.

As a result, the electrical conductivity of insulators is not exactly zero but is extremely small, typically in the range of $10^{-20}$ to $10^{-10}{\Omega }^{-1}{\text{m}}^{-1}$.

Answer: extremely small