notes chapter 1 electricity electricity- electricity is the important source of energy since it is used in tranportation industries and at our homes too types of electric charges- 1. positive charge- ++ 2. negative charge- -- 1. opposite charge or unlike charge attract each other 2. similar charge or like charge repel each other SI unit of electric charge is coulomb conductors- those substance through which electricity can flow are called conductors. ex- metals like silver,copper,aluminium insulators- those substances through electricity cannot flow are called insulator ex - plastics,rubber,paperetc. electric potential- electric potential at a point in electric field is defined as a moving a electric charge from one point to another potential difference- potential difference is a state of system when one part of system keep at high potential and other part keep at low potential p.d= work/charge v=w/q ...