Electricity

Objectives

---

- To know the sources of electricity - To be aware of the equipments working on electricity - To know the different kinds of electric cells and understand their applications - To be able to use different types of cells in different applications - To understand the symbols of circuits and apply them in different circuits - To identify conductors and insulators - To be able to make their own batteries

Summary

---

- Any device from which electricity is produced, is called the source of electricity. - There are many sources of electricity such as thermal power stations, hydel electric power stations, wind mills, atomic power station etc. - Device that converts chemical energ into electrical energy is called a cell. - Electric cells are of two types depending on the continuity of flow of electric current. - Primary cell is a cell that is designed to be used once and discarded. - A cell that can be recharged many times is called secondary cell. - Two or more cells combined together to make a battery. - An electric circuit is a combination of cells, key, bulb and connecting wires arranged in proper manner. - A circuit consisting of a cell, key, bulb and connecting wires is called a simple circuit - If two or more bulbs are connected in series in a circuit, then that type of circuit is called series circuit. - If two or more bulbs are connected in parallel in a circuit, then that type ofcircuit is called parallel circuit. - Symbols of electrical components are used to represent complicated circuits in simple way. - The materials which allow electriccharges to pass through them are called conductors. - The materials which do not allow electric charges to pass through them are called insulators or non-conductors.