Electricity deals with the flow of electric charges through a conductor; as a common term it refers to a form of energy. Electric current is used in houses, educational institutions, hospitals and industries, so its generation and transmission is a very crucial aspect of our life. This chapter covers current, potential difference, Ohm's law, resistivity, resistors in series and parallel, the heating effect of current, electric power and energy, domestic circuits, and LED bulbs and LED television.
1. Electric Current
- The motion of electric charges (electrons) through a conductor (e.g., copper wire) constitutes an electric current – similar to the flow of water through a channel, or air from a region of high pressure to a region of low pressure.
- Definition: Electric current (symbol I) is the rate of flow of charges in a conductor – the amount of charge flowing through any cross section of a conductor in unit time.
- If a net charge Q passes through any cross section of a conductor in time t, then I = Q / t.