库仑定律 / Coulomb's Law
静电力: —
—
正电荷 +
负电荷 −
→ 力方向
电荷 q₁ (左侧)
电荷 q₂ (右侧)
距离与半径
演示要点 / Key Points
F
同号相斥，异号相吸
Like charges repel, opposites attract.
r²
平方反比 F ∝ 1/r²
Force inversely proportional to distance squared.
E
电场线从正到负，永不相交
Field lines start at +, end at −, never cross.
R
带电金属球，内部E=0
Conducting spheres — field starts at surface.