Introduction about current electricity

 

           In the chapter of heat, you have studied that heat is a form of energy. The other forms of energy are lights,mechanical and chemical energy,etc. Among all forms of energy electricity and electric energy is the most useful and convenient for mankind. It can be converted to almost all forms of energy easily and can be stored and transmitted over long distances with little wastages.  Electric bulbs , Motors, all phones , air conditioners , heater , computers and heavy machinery all uses different effects of electric energy. In fact it is difficult to imagine our lives without electric energy.  The origin of electric energy lies in electric charges. The branch of physis which deals with the study of electric charges and their effects is called electricity.                                                                                                                                                 In orders to understand the topic of electricity better, we shall first recall some of the properties of electric charges which you have studied in details in previous classes.

ELECTRICS CHARGE-PROPERTIES

1. Electric charges is of two types viz. positive and negative charges. proton is said to be charged positively and electron is said to be charges negatively.

like charges repel annd unlike charges attract.Thus a proton repels proton and attract electron.

2.The forces of attraction or repulsion between two charges is given by coloumb law.

3. Charges can neither be createde not destroyed.The charges from one body can be transferred to another body but the total charges of a system remains constant.This is called law of conservation of charges.

4. Protons and electrons are elementary charged particles. though the charge on them in opposite in nature, the magnitude of charge passed by them is same.charge on a body is always an integral multiple of this value. This is called quantization of charge.

5. When a body gains electrons.it becomes negatively charged.when it loses electrons it becomes positively charged.The positive charge being bound firmly in it nucleus does not participate in charging.

The study of electricity is classified in two parts:- 1. static electricity:-It deals with electric charge at rest and their effects. 2.Current electricity:-It deals with charges in motion and their effects. This chapter deals with charges in motion i.e. current electricity.