Electricity is one of the most useful forms of energy in modern era. Due to invention of electric energy, varieties of work can be done in a simple and easier way. Switch on and enjoy cool air in hot summer with the help of fan/air conditioner, get light energy in absence of sun light, use refrigerator and keep vegetables and other things fresh for so many days. Getting bored put TV on and enjoy programme available for our entertainment. Our life is well dependant on the electric appliances. (Shown in picture below.)
We know that all above listed devices works on electric energy, which can be carried with the help of electric current. For explanation of electric current, we need to discuss the structure of materials. As we know that materials around us are divided into three categories viz. Metal, Non metal and Metalloids. Out of these only metals are used for carrying electric energy. Metals are considered as good conductors for heat and electric energy, due to presence of some loosely bounded electrons in the last orbit of its atom. These loosely bounded electrons when given some can travel inside the metal with certain speed and produces electric current.
Electrons from each atom of metal which are loosely bounded in it, passes through metal and produces electric current. Then electric current can be defined as the amount of flow of electrons through given cross-section of metal wire in given unit of time.
If ‘e’ be the charge on electron, and there are total ‘n’ electrons then total number of electrons travels through the wire in time ‘t’ gives electric current ‘I’.
The SI unit of electric current is ampere (A), in the honour of greatest physicist Sir Andre Ampere, who has invented the instrument Ammeter for measuring current.
When current flows through metal, it carries electric energy, which is useful for many appliances such as electric iron, television, refrigerator etc.
In this modern world, biggest revolution which is going to takes place in coming decades will be in electric energy only. Electric vehicles are the future of world, as the cost of crude oil (petrol/diesel) is going beyond capacity of common man. So it’s our duty to use electric energy wisely so that it will retain with us for long time. Focus on renewable energy sources like solar energy, which is available at free of cost and completely pollution free.
Question and Answer:
Q. List the household instruments which use electric energy?
Ans: Electric iron, refrigerator, Television, Fan, Air conditioner, Electric heater/geyser etc.
Q. Why only metals can carry electricity?
Ans: In metals only, large numbers of loosely bounded electrons are available which can get removed from the orbit of an atom of and can travel through metal; hence only metals can carry electricity.
Q. Define electric current.
Ans: The amount of flow of electrons through given cross-section of metal wire in given unit of time.
Q. State the unit of electric current.
Ans: SI unit of electric current is ampere (A).