Field Theory - Conduction And Convection Current Density....
CONVECTION CURRENT DENSITY: - Convection current occurs in insulators or dielectrics such as liquid, vacuum and rarified gas. - Convection current results from motion of electrons or ions in an insulating medium. - Since convection current doesn’t involve conductors, hence it does not satisfy ohm’s law. - Consider a filament where there is a flow of charge ρ v at a velocity u = u y a y . - Hence the current is given as: Where u y is the velocity of the moving electron or ion and ρ v is the free volume charge density. - Hence the convection current density in general is given as: J = ρ v u CONDUCTION CURRENT DENSITY: - Conduction current occurs in conductors where there are a large number of free electrons. - Conduction current occurs due to the drift motion of electrons (charge carriers). - Conduction current obeys ohm’s law. - When an external electric field is applied to a metallic conductor, conduction current occurs due to ...