Friday, February 21, 2014

what are conductor semiconductor and insulators?

Hello! Guys want to know about Conductor, Insulator, and Semi-conductor. So,

What are conductors, Insulators, and Semi-conductor?

Introduction:-
          Everybody in the universe allow electricity to pass-through within it. Some of them are allow mature amount of electricity, some allow less and some approximately nil.

-         So, there are three main types of category.
1.     Conductor
2.     Semi-conductor
3.     Insulator
Definition of Categories:
1.   Conductor:-
                    The bodies which can allow mature amount of electricity pass-though from it are called Conductors.
-         The Conductor are commonly used in various type of field of electricity, magnetism, and also electromagnetism.
-         They are also used for making magnet by different method like single-touch method.
-         E.g. Iron, Gold, and Metal are generally considered as conductor. 

2.   Semi-conductor:-
                 The bodies which can allow less amount of electricity to pass-through from it are called semi-conductors.
-         The Semi-conductor are generally used for making electronic devices.
-         E.g. Silicon, Germanium are example of Semi-conductors, and mobile, television are example of electronic devices.
3.   Insulator:-
                 The bodies which can allow very low amount of electricity or approximately equal to nil are called Insulator.
-         The bodies which have high amount of resistance or ability to resist to electricity is also called Insulator.

Why they bodies behave different so categories into different category.  

             For getting the answer of we have to study the band theory of solids,
One of the active field of research called Solid state Physics. It deals with the structure and electrical properties of solids. According to Bohr Atomic model electron in a single atom can occupy only certain energy –level. The lower possible energy level is called the ground state and higher ones are called excited states. When atom or molecules are in solid-state, their outer-electron overlaps. Hence, their energy level are changed some-what and because of interaction, the energy level are spread out into energy bands. The outer electrons can be considered to be in either of two bands. The lower valence band, which corresponds to the ground state; or the upper conduction band. No electron can have energy in the “for-bidden” energy gap between the two bands. Normally the electron resides in the valence band where they are held more tightly to individual atom.
                     In an Insulator, the valence band is full, the conduction band is essentially empty, and the forbidden gap is fairly large. Hence normally, there are no free state for the electrons to move into higher conduction band.
                    In a conductor, there is no gap and the two band usually overlap or there is simply one band that is not filled and the electrons are free to move easily to other state.
                    In the pure semi-conductor the forbidden energy gap between valence and conductor bands are narrow.
                    So, due to gap in between conduction band and valance band in substance conductivity and resistivity increase or decrease.

                    As we know that conductivity and resistivity are inversely proportional to each other. So, if the gap increases resistivity increases and conductivity decrease. Hence, it categories into Insulator and vice versa.



   



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