why it is given that coal is bad conductor of electricity.It contains carbon and pencil lead is graphite which is also carbon then " WHY IS COALBAD CONDUCTOR OF ELECTRICITY "

Because Carbon Is A Non Metal And A Poor Conductor Of Electricity.

But Carbon In The Form Of Graphite Is A Good Conductor Because Graphite Has A Hexagonal Structure And Valency Of Carbon Is 4 But In Case Of Graphite 1 Electron Is Joined To 3 Other Electrons To Form Graphite Crystal.As A Result 1 Electron Remain Free From Vander Vaals Forces.Hence Due To The Presence Of Free Electron Graphite Conducts Electricity.

But In Case Of Other Forms Of Carbon The Structure Is Different Therefore Hence No Free Electrons So No Conduction Of ELectricity.