Question

The range of electrical conductivity for insulators is (in $oh{m^{ - 1}} \cdot {m^{ - 1}}$)?
(A) ${10^{ - 7}}$
(B) ${10^{ - 11}}$
(C) ${10^{ - 9}}$
(D) ${10^{ - 8}}$

Answer 1

Electrical conductivity is the ability of a material to conduct electricity. Free or mobile electrons are required in order to be conductive material for the solids. Insulators can conduct negligible amounts of electricity.

Complete step by step solution:
We know that depending upon the conductivity of the solid materials, the solids can be categorized into three categories namely conductors, semi-conductors and insulators.
- The solids that can conduct electricity are due to the presence of free electrons in their structure.
- An electric insulator is a material is a material in which the electrons are not able to move freely or they have tightly bound electrons that are not mobile. However, very little current can still flow through them.
- We can say that the insulators have very high resistivity in comparison to the conductors. A perfect insulator does not exist as a material has some number of mobile charges that can move around.
- The range of electrical conductivity for the insulators is ${10^{ - 20}}$ to ${10^{ - 10}}$ $oh{m^{ - 1}} \cdot {m^{ - 1}}$.
- Conductors and semiconductor materials have electric conductivity of ${10^4} - {10^7}oh{m^{ - 1}} \cdot {m^{ - 1}}$ and ${10^{ - 6}} - {10^4}oh{m^{ - 1}} \cdot {m^{ - 1}}$ respectively.
- Materials like glass, paper, and Teflon polymer are good examples of insulators. So, some of the insulating polymers can be used as a coating for the electric wires and cables.
- Thus, we can say that ${10^{ - 11}}oh{m^{ - 1}} \cdot {m^{ - 1}}$ is in the range of the electrical conductance of the insulators.

So, the correct answer is (B).

Note: Remember that as we give large amounts of voltages on the insulators, even they become conductive for electricity. This voltage is known as the breakdown voltage of the insulator.