Charge
Charge is the intrinsic property of matter due to which it attract or repel other charged matter.
Origin of change
The origin of charge is not found yet. The force exerted by charges is called natural force.
Point charge
A charge whose distance from other charge is much more than its size is called point charge
Coulomb's law is only applicable for point charges. So understanding the concept of point charge is very important.
Test Charge
A Test Charge is one whose self electric-field is negligible. It is used to test the strength of a point charge at certain place from that point charge. The nature of this test Charge is always positive.
