1.1 Coulomb law 1.1.1. What is electric charge? This is a question never be answered EC is a quantity derived from electric phenomena 1.1.2. How to define the electric charge? 1 Coulomb. In MKsAunit system, 1C=1A1S Concept: The observatory phenomena is attraction, the measurement quantity is the force, therefore the electric charge is only a definition in the beginning, but lateron 1.1.3. Character of the electric charge Quantum unit of the charge: charge for electron e=1. 6021892X10-19C Conservation of the charge (how to understand the creation of the charge?), Difference with mass(deep discussion 1.1. 4 Torsion experiment and coulomb law Physics starts from torsion pendulum experiments and continues with torsion pendulum experiments The description of Coulomb law: The force between two point charges is proportional to the product of charges and inversely proportional to the square of the distance1.1 Coulomb Law 1.1.1. What is electric charge? This is a question never be answered. EC is a quantity derived from electric phenomena. 1.1.2. How to define the electric charge? 1 Coulomb . In MKSA unit system, 1C=1A1S Concept: The observatory phenomena is attraction, the measurement quantity is the force, therefore the electric charge is only a definition in the beginning, but later on……. 1.1.3. Character of the electric charge Quantum unit of the charge: charge for electron, e=1.6021892X10-19C Conservation of the charge (how to understand the creation of the charge?); Difference with mass (deep discussion) 1.1.4. Torsion experiment and Coulomb law Physics starts from torsion pendulum experiments and continues with torsion pendulum experiments. The description of Coulomb law: The force between two point charges is proportional to the product of charges and inversely proportional to the square of the distance