This chapter begins with the introduction of two types of electric charges, i.e. positive and negative charges. The SI unit of charge is Coulomb. The substance which allows electricity to flow through them is called a conductor, and which does not allow free flow of charge is called insulators. Further, the knowledge about electric potential and potential difference, their formulas, and SI unit is provided in the chapter. A voltmeter is a device employed to measure the potential differences between two points.
Electricity can be of two types: static and current electricity. Electric current is the flow of electric charges across a conductor. Its SI unit is ampere and is measured by an instrument called an ammeter. The chapter includes demonstrating how to get a continuous flow of electric current and how the current flows in a wire. Electric circuits, symbols used for indicating electronic components in a circuit, and the two types of circuit diagrams, i.e. open and closed, are also explained.
This chapter includes one of the most fundamental physics laws, 'The Ohm's Law', its derivation, and conclusion.The resistance of a conductor is defined as its ability to hinder the flow of current. The flow of current through it depends on the length, thickness, nature of the material, and temperature of the conductor. All the substance in this world can be divided into the following three groups based on their electric resistance:
The concept of resistivity helps us understand which material can be used to make wires, blub elements, or heating elements of an electric iron. The resistors can be placed in two ways in the circuit, i.e. in series or parallel in various combinations, and their resultant resistance can be calculated. Household electric circuits are linked in parallel connection due to certain disadvantages of series circuits and comparative advantages of parallel circuits, which we'll study in the latter half of this chapter.
Finally, the concept of electric power, its unit, and various formulas for calculating electric power is introduced. The power-voltage rating of various appliances and the current drawn by them are studied. Students learn about the relation between the commercial unit of electric energy, i.e. kilowatt-hour and joule and how to calculate the cost of electrical energy consumed in a household every month. The chapter concludes with the heating effect of electric current and its applications.