Electrostatics

Electrostatics:-

• Electrostatics is the study of electric charge at rest.
(Or more or less at rest, in contrast with current electricity.)


Electrical Charges:-

• Electric charge is a fundamental property of matter.

Two types of electric charges:
• Positive charge - every proton has a single positive charge.
• Negative charge - every electron has a single negative charge.


• An object with an excess of electrons is negatively charged.
• An object with too few electrons (too many protons) is positively charged.
• An object with the same number of electrons and protons is neutral.


• Like charges repel.
• Opposite charges attract.

Elementary Charges:-

• Protons carry the smallest positive charge.
• Protons and uncharged neutrons generally reside in an atom’s nucleus.
• Protons are held in the nucleus by the strong force.

• The smallest negative charge is the charge on the electron.
• In normal atoms, electrons orbit the nucleus.
• The electric force between electrons and protons supplies the centripetal force to keep electrons in the atom.

• The charges carried by the proton and electron are equal in size.
• The mass of the proton is about 2000 times the mass of the electron.


Units of Charge:-

• The SI unit of charge is the Coulomb.

1 Coulomb = the charge of   (6.24 x 10^18)   electrons.

e   =   (1.602 x 10^-19)   C


Charge is Conserved:-

• Electric charge is conserved:
– Electric charge moves from one place to another: (no case of the net creation or destruction of electric charge has ever been observed.)
• In solids, only electrons can move.
• In liquids, gasses, and plasma, both positive and negative ions are free to move.