ch 1: electrostatics

Electrostatics: Study of charges and their properties when they are at rest.

Excess charge or surplus charge: A body is said to be neutral if it contains equal number of protons and electrons.

But if the electrons are more in number, it is said to be negatively charged. If the electrons are less in number than the protons, then it is said to be positively charged.

Methods of giving excess charge to a body:

1. By friction: When a glass rod is rubbed by a silk cloth, electrons get transferred from glass to silk. The glass rod becomes positively charged, while the silk cloth negatively charged, by the same amount.