Positive, Glass (rubbed with silk), Perspex (rubbed with wool)
Negative, Amber (rubbed with fur), Rubber (rubbed with fur), Polythene (rubbed with wool)
Like charges repel
Unlike charges attract
The atom that loses an electron is now a positive ion, and the atom that receives an electron is a negative ion. At no time during this process is charge ever created or destroyed.
Induction is the production of electric charge on the surface of a conductor under the influence of an electric field. The neutral metal spheres will possess equal amounts of opposite charge at the end of the process. The advantage of charging by inducton is that it can be repeated many times without any loss of charge from the inducing specimen.
An electric field is a region in which an electric charge experiences a force
An electric field line is the path a positive charge would take if it is free to move. The direction of the electric field lines gives the direction of the force acting on a positive test charge.
Lines must begin from positive charges to negative charges
No two field lines can cross
Number of lines drawn for a positive or negative charge is proportional to the magnitude of charge