# ELECTRIC CURRENT or CURRENT ELECTRICITY

### electric current –

Electric current –

When electric charges is in motion , they constitute what is called an electric current . electric current is defined as the rate of flow of charge through an area of the conductor . if  Q is the charge flows through a conductor in time T then  electric current I = Q/T

Or  I= dQ /dt . unit of current is Ampere .

We can define 1 Ampere  is the current flowing through a conductor when 1 Coulomb  of charge flows through a conductors in unit time.

In the terms of drift velocity current I = n e A Vd  where n is the charge density , A  is the area of cross-section of the conductor , e is the charge on electron and Vd is the drift velocity.

In terms of Ohm’s law – current  I = V/R  V is the potential difference across the conductor and R is the resistance of the conductor .

So we can say 1 Ampere current flows through a conductor when unit potential difference setup across a conductor of resistance 1 Ohm .

Ampere is the basic unit of electric current . It is named after Andre-Marie -Ampere a French scientist  born in 1775  . He also known as the father of electrodynamics .

Definition of Ampere –  1 Ampere  is the current flowing through a conductor when 1 Coulomb  of charge flows through a conductors in unit time.

From Ohm’s law – potential difference across the conductor is directly proportional to the current flowing through the conductor , if V  is the  potential difference across the conductor and I be the current flowing through the conductor then according to Ohm’s law V α I or V= RI , where R is the resistance of the conductor . ( resistance of a conductor is the property of the conductor to restrict the flow of current through it) i.e. current  I =V/R,

So we can say, 1 Ampere current flows through a conductor when unit potential difference setup across a conductor of resistance 1 Ohm .

Another definition of current can be determined using the property of force between two parallel current carrying conductor according to it force between two parallel current carrying conductor can be given as force per unit length (f/l) F= µ0I1 I2 /2Πd ( Here I1 and  I2 are the current through the wires and , d is the separation between them . according to given relation we can define, 1 Ampere is the current which when flowing in each of parallel conductors placed at separation  1 m in vacuum exert a force of 2 x 10-7 N on 1 meter length of either wire.