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Definition of Voltage and Unit of Voltage

Electric potential difference between two points in a material is voltage. Where electric potential is work required to move electric charge between two points in electric field. When voltage is applied between two points in a material, Electric field pushes electrons to positive charge direction. The volt is named in honor of the Italian physicist Alessandro Volta (1745–1827) who invented first chemical battery.

Electrons movement by Voltage

If available electric potential per single electron is more than fermi-energy-level, Then electrons jump from valance bands to conduction band and move towards next electron gap. thus electrons replace each other continually. Each moved electron absorbs electric potential energy which is converted to thermal energy amount of absorbed energy depends on material physical properties. Hence voltage is called EMF or Electro-motive-Force. Electron enter and emit from material block within no time. However Individual electron velocity is much lower and is called drift velocity. This charge flow is called current , and material capability to absorb electrical energy is resistivity. Flow of charge generate also magnetic flux.

Units of Voltage

SI unit of voltage is volt. 1 volt is equivalent to electric potential difference which can move 1 Coulomb charge between two points using 1 Joule work done. On volt is equal to

V = {1J  \over 1C}