Chapter 19 Electric Charge and Electric Field 1. Point charge(点电荷)(p461) 当带电体的线度与它到其它带电体之间距离或到 研究点之间的距离相比足够小时(d<<r),可忽略其大 小,将电荷看成集中于一点的带电体,称点电荷 The sizes of objects are much more smaller than the distance between them 2. Coulombs law With the torsion balance(扭称实验) Coulomb esta blished the coulomb's law of electrostatic interaction.Chapter 19 Electric Charge and Electric Field 1. Point charge (点电荷) (p461) 当带电体的线度与它到其它带电体之间距离或到 研究点之间的距离相比足够小时(d<<r), 可忽略其大 小,将电荷看成集中于一点的带电体，称点电荷. The sizes of objects are much more smaller than the distance between them. With the torsion balance (扭称实验)Coulomb established the Coulomb’s law of electrostatic interaction: 2. Coulomb’s Law