How current is formed in conductors ?

Explanation

`rArr` When conductor are subjected to electric field, electric charge experience force.
`rArr` If charges are free then they will move and current will be formed.
`rArr` In nature free charge exist in upper strata of the atmosphere called Ionosphere.
`rArr ` In atom and molecules Coulombian force act between electron and nucleus hence electrons are not free.
`rArr ` Bulk matter is made up of nwnber of molecules.
`rArr` l gram of water contain about `10^(22)` molecules. These molecules are so closely packed so that individual electron are no longer attached to nucleus.
`rArr` In some materials electrons are bound hence even after applying electric field they do not get accelerated.
`rArr `In metals some of electrons are practically free to move hence they move randomly in bulk material.
`rArr` When external electric field is applied to metals electric current is produced.
`rArr` In solid conductors current is formed due to motion of electron.
`rArr` In liquid (electrolyte) current is produced due to motion positive and negative ion in mutually opposite direction.
` rArr` In gases also current is produced due to motion of ions.