Electrostatics
2.0 Electric charge
2.0 Electric charge
When any two different materials are rubbed together they exert forces on each other and each is said to have acquired an electric charge.
Electric charge like mass is one of the fundamental attributes of the particles of which the matter is composed of. The charge is the physical property of certain fundamental particles (like electron and proton) by virtue of which they interact with the other similar fundamental particles.
To distinguish the nature of the interaction, charges are divided into two parts.
- Positive
- Negative
Like charges repel each other while unlike charges attract.
In nature, atoms are normally found with an equal number of protons (positively charged particles) and electrons (negatively charged particles). Thus atom is electrically neutral.
The charge on an electron or a proton is the smallest amount of free charge that has been discovered.
Charge on proton: $ + 1.6 \times {10^{ - 19}}C$
Charge on electron: $ - 1.6 \times {10^{ - 19}}C$
1 coulomb $ = 3 \times {10^9}\,esu$
1 coulomb $ = \frac{1}{10}\ emu$ of charge
Charges of larger magnitude are built up on an obejct by adding or removing electrons. If in a body there is excess of electrons over its natural configuration conventionally the body is said to be negatively charged and if there is deficiency of electrons it is said to be positively charged.
$-ve$ charged body: Body has gained electrons
$+ve$ charged body: Body has lost source electrons
