Electric Charges and Field

Electric Charge

The physical properties of  matter that causes it to experience force when placed in an electromagnetic field is called charge. Electric charge is Scalar quantity. 

There are two kinds of charges.

  • Positive Charge 
  • Negative Charge 
An object can attend a positive charge by lossing electron. While another attend negatively charge by gaining electron. Like charges, repel eachother while unlike charges attract eachother. An object can be charged by different methods like; friction, conduction and insulation etc.

Conductors

Those substances which can be used to carry electric charge from one point to another and allow electricity to pass through them is called conductors. e.g; Fe, Cu, etc.

Insulator

Those substances which cannot conduct electricity are called Insulator or dielectric. e.g; glass, wood etc.

                                                Basic properties of Electric Charge 

Additive Nature of Charges Electric charge is additive in nature it means if a system consist of n charge `q_{1},q_{2},......q_{n}` then the total charge of the system will be `q_{1}+q+{2},......q_{n}` In order to calculate the net charge on a system we have to just add algebrically all the charges present in the system this is known as the principle of superposition of charges.

Conversation of Electrical charge During any process the net electric charge of an insulated system remain constant it means charge can neither be created nor be destroyed but it may br transfered from one part of system to another this is called conservation of electric charge.

Quantisation of Electric charge The charge on any body can be express as an integral multiple of basic unit charge e this is called quantisation of electric charge, it can be writen as `[q=\pm ne]` where n=1,2,3,..... The SI unit of charge is coloum and it is denoted by C. The value of unit charge` [e=1.6\times 10^{-19}c]`