Electricity and Circuits Class 6 Notes CBSE Science Chapter 12 (Free PDF Download)

Definition of Electricity:

Electricity is the flow of electrical power or the charges (electrons) through a proper medium commonly the wires we see in our homes. The source of electric currents can be through a battery, generators, invertors, dry or electric cells and might be converted from other sources of energy.

Electric Circuit:

Electric circuit is a closed path that provides a continuous flow of electrons or electric current from a voltage or current source to the equipment being used. In a circuit, the current is said to flow from one terminal of a power source or say a cell to another terminal. Generally, the starting terminal is taken as positive and the ending terminal as negative. A basic circuit can be a bulb connected to a battery by means of two wires such that the bulb starts glowing given the battery isn’t dead and the bulb is not fused.

This path of current flow or a circuit can be represented using various symbols and notation for different components and is called a circuit diagram.

Open and Closed Circuits:

The path travelled by the electric current from one terminal to its other terminal when it is unbroken and continuous then it is called a closed circuit and if the same path is broken somewhere along the path that stops current to flow continuously is called an open circuit.

Electrical Components:

1. Wires: These are the electrical conductors used to connect two or more electrical components and allow the flow of current. The wires are generally made of metals that are good conductors of electricity and based on the usage, the type of metal and the dimension of wire is selected.

2. Bulb: It is a glass case composed of a filament inside it connected to the two terminals and which gets heated up upon the passage of electric current and emits light. The filament wire is generally made up of coiled tungsten wire. The electricity is supplied through the two terminals between which the filament is present.

3. Electric Cell or Dry Cell: It is a kind of device that stores chemical energy and converts it into electrical energy that can be used for different purposes. It has two terminals namely positive and negative. Inside a cell, the charges flow from the negative terminal to positive terminal while the reverse happens outside the cell.

4. Battery: This is made up of a combination of two or more cells combined in a series configuration.

5. Switch: It is a simple device used in an electrical circuit to allow or restrict the continuous flow of current. It is placed between a gap in a circuit and when turned on, it fills the gap with a conducting medium making the circuit work and when off breaks the circuit by removing the conducting medium from the gap.

The above components together can be seen in an electric torch that consists of connecting wires, battery and an LED (Light Emitting Diode) bulb.

Electrical Conductors and Insulators:

Electrical conductors are the materials that allow the flow of electricity through it. All the metals come under the category of good conductors of electricity. Among non-metals only carbon can conduct electricity which can be experimented by connecting wires across the two ends of a pencil.

On the contrary, the materials that do not allow electric currents to flow through it are called the bad conductors or the insulators. Some examples of insulators are plastic, rubber, dry wood, PVC etc.

Effects of Electricity:

The flow of electric current through a material is accompanied with some other effects which sometimes are used for other purposes or causes energy losses. Some of the effects are as follows;

• Heating Effect: This effect is used in electric heaters, ovens, etc.

• Lighting Effect: The primary example is an electric bulb.

• Magnetic Effect: Used in electromagnets.