Question

Which of the following represents the correct order of conductivity in solids?
A. ${K_{metals}} > > {K_{insulators}} < {K_{semiconductors}}$
B. ${K_{metals}} < < {K_{insulators}} < {K_{semiconductors}}$
C. ${K_{metals}};{K_{insulators}} > {K_{semiconductors}} = zero$
D. ${K_{metals}} > {K_{insulators}} > {K_{semiconductors}} \ne zero$

Answer 1

Hint:As per the question, here the correct order of conductivity in solids means, which is a good conductor of heat and electricity will come first, and then the lowest in conductivity. As we know, to prevent electricity, we use insulators to cover-up the metals.

Complete answer:
Metals have free electrons in them, which helps largely in the conduction of electricity. So, they have the highest conductivity. Because the atoms in metals form a matrix through which outside electrons can easily travel, metals are good conductors of electricity and heat.They generate a sea of electrons around the positive nuclei of the interacting metal ions, rather than orbiting their particular atoms.

Free electrons are not present in insulators. As a result, electricity is unable to travel through the insulators. As a result, their conductivity is the lowest. Insulators are necessary to keep humans safe from the effects of electricity. A rubber-like insulator prevents you from being electrocuted by covering the wire that transmits electricity to your computer or television.Glass, air, and paper are all good insulators.

Temperature affects the conductivity of semiconductors. They act as insulators at room temperature. However, as the temperature rises, the semiconductor's conductivity rises as well. So, the correct order will be ${K_{metals}} > > {K_{insulators}} < {K_{semiconductors}}$.Silver has the highest electrical conductivity, followed by copper and gold. Silver also has the highest heat conductivity and light reflectance of any element.

Hence, the correct option is A.

Note: At absolute zero, semiconductors are perfect insulators. However, at ambient temperature, the density of electrons in the conduction band is not as high as in metals, hence they cannot conduct current as well as metals. Electrical conductivity of semiconductors is not as great as that of metals, but it is also not as low as that of insulators.