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## 章节主题：

Concept of an electric field
Electric force between point charges
Electric field of a point charge
Uniform electric fields
Electric potential

## 学习目标：

(a) Show an understanding of the concept of an electric field as an example of a field of force and define electric field strength at a point as the electric force exerted per unit positive charge placed at that point.

(b) Represent an electric field by means of field lines.

(c) Recognize the analogy between certain qualitative and quantitative aspects of electric and gravitational fields.

(d) Recall and use Coulomb's law in the form F = Q₁Q₂ / 4πε₀r² for the electric force between two point charges in free space or air.

(e) Recall and use E = Q / 4πε₀r² for the electric field strength of a point charge in free space or air.

(f) Calculate the electric field strength of the uniform field between charged parallel plates in terms of the potential difference and plate separation.

(g) Calculate the forces on charges in uniform electric fields.

(h) Describe the effect of a uniform electric field on the motion of charged particles.

(i) Define the electric potential at a point as the work done per unit positive charge in bringing a small test charge from infinity to that point.

(j) State that the field strength of the electric field at a point is numerically equal to the potential gradient at that point.

(k) Use the equation V = Q / 4πε₀r for the electric potential in the field of a point charge, in free space or air.

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