CURRENT ELECTRICITY

Introduction
The branch of physics which deals about the motion of electric charges is known as current electricity.When certain amount of charge is given to an insulator, it is deposited at a point, which is named static charge. The study about the properties of static charge is known as electrostatics. Charge can also be stored in a conductor, when it is surrounded with insulating material. If the charge is added to end of a metallic conductors like silver, copper, aluminium, etc., potential difference is created between two end, hence, they readily move from one end to another. This dynamics (motion) of  charge ls dealt in current electricity.

 In metallic conductors, the electrons in the outermost orbits are loosely bound to their respective atoms, So, they can easily travel from one atom to neighboring atoms, these electrons are called free electrons. However, the motion of free electrons in a conductor is completely random. If a certain potential difference is created by any means across two ends of a conductor, the direction of motion of the electrons is specific. This unidirectional flow of charge particles (electrons) creates electric current. The electron which take part in the electric current are called conduction electrons

Electric Circuit
A closed path containing the electric source and other electric components like resistor, switch, etc.,
Is known as electric circuit. If the oppositely charged conducting plates are connected by a metal
wire, the charge particles move from higher potential to lower potential, Conventionally, charge
flows from positive plate to negative plate as shown in Fig. (i). In reality, electrons move from
negative charge plate to positive charge plate as shown in Fig. (ii), but we describe the direction
of movement of charge in conventional way (from positive potential to negative potential). The wire
serves as a charge pipe through which the charge can flow (similar to water flow in water pipe).
Moreover, charge can flow from positive to positive terminal (also negative to negative terminal), if
they have the different electric potential as shown in fig. (iii)