Electrostatics is the branch of Physics which deals with electric charges at rest and their properties.
When two suitable objects are rubbed against each other, charges appear on them. The electric charges acquired by them are immovable and they are called static charges and the electricity so produced is called static electricity. Since the charges are produced by rubbing or friction, the electricity so produced is also called frictional electricity.
Origin of frictional electricity
Two kinds of charges
Charges are of two kinds; positive and negative. Initially when charges were discovered the two kinds of charges were called Rosie nose and vitreous. The charge acquired by Amber when rubbed with wool or fur The charge acquired by Amber was called resinous because Amber is formed from fossilised resin. The charge acquired by glass rod whenRubbed with silk is called vitreous. The term vitreous means glass like Missed chances will need to read named negative and positive by Benjamin Franklin. The charge acquired by Amber Is termed negative and the charge acquired by Glass is termed positive
Properties of charges
Like charges repel and unlike charges attract
repulsion is the sure test for charging
methods of charging
Charging by induction
charging by conduction
induction precedes attraction
Quantisation of charge (graininess or discreetness )
The charge present in any body is an integral multiple of the fundamental charge, the charge on an electron (1.6 x 10 -19 C)
Q = ne; Where n is an integer, positive or negative
Recent researches have established the existence of quarks which build up subatomic particles like protons and neutrons. The courts have fractional electronic charge like 1/3 e, 2/3 e etc. But this will not violate the quantisation of charge because first of all in our ordinary world Cox do not exist freely they always combine to form protons neutrons or other particles having integral multiple of electronic charges. Even if they are found to exist independently it only reduces the magnitude of the fundamental charge to the lowest of the charge on an independent quark.
law of conservation of charge
The law of conservation of charge states that charges can neither be created nor be destroyed in isolation. It is impossible to create a net positive charge or a net negative charge. Charges can be produced or destroyed only in equal and opposite Pairs
annihilation of matter and paint production
differences between mass and charge
Coulomb’s law in vector form
Principle of superposition
continuous charge distribution