Superposition Principle 电场强度叠加原理 F4=geNet t 92V 4(+E2+E 3 1 Location of ge 4 E E neSuperposition Principle 电场强度叠加原理 - + q1 q2 ( ) 4 1 2 3 4 4 net q E E E F q E      = + + = q + 3 Location of q4 E1  E2  Enet  E3 