The movement of electric charge is known as an electric current, and its intensity is measured in amperes. And electric refers to the number of charges that move through the wire per second. Voltage is sometimes called electric potential and is measured in volts.
Current: Current is defined as the rate of flow of charge. I=Q/t, where Q is the charge that flows through the cross-section of a conductor in time, t.
Electric current can be generated by moving a metal wire through a magnetic field. It is also different than static electricity, which is the accumulation of charges on a surface. Electric generators rotate a coil of wires through a magnetic field.
There are two types of electrical current: direct and alternating. In a direct current, abbreviated DC, the electrons move in one direction. Finally, the unit of current is the ampere, which is defined as one coulomb of charge passing a given point in one second.
Points included in this chapter are the concept of charge, the concept of the current, concept of potential and potential difference, the concept of resistance, ohm’s law (V = IR), experimental verification of ohm’s law, ohmic and non-ohmic resistors, factors affecting the resistance of a conductor, specific resistance (or resistivity), choice of material of the wire, superconductors, an electromotive force (EMF) of a cell, the terminal voltage of a cell, the internal resistance of a cell, a combination of resistors, electrical energy, measurement of electrical energy (expression W = QV = V/t), electrical power and its expression P = W/t = VI, a commercial unit of electrical energy, a power rating of common electrical appliances, household consumption of electrical energy, the heating effect of current.