816.2 The electric field of static charge and electric field lines Notice OThe electric field depends on the shape and the distribution of the charges @the gravitational force is always parrallel to the gravitational field in the gravitational case. but the electrical force can be either parallel or antiparallel to the electric field The force on a positive charge +q is parallel to the electric field. the force on a negative charge-g is antiparallel to the electric field F=gE 816.2 The electric field of static charge and electric field lines 2. The electric field of pointlike charge distribution Test F charge F 4兀E021 Q F10 For +O E q za q7 Notice: 1The electric field depends on the shape and the distribution of the charges. 2the gravitational force is always parrallel to the gravitational field in the gravitational case, but the electrical force can be either parallel or antiparallel to the electric field. The force on a positive charge +q is parallel to the electric field, the force on a negative charge -q is antiparallel to the electric field. F qE r r = §16.2 The electric field of static charge and electric field lines §16.2 The electric field of static charge and electric field lines 2. The electric field of pointlike charge distribution Test charge r r F q r Q 2 21 0 21 ˆ 4 1 r r qQ F πε = r r r Q q F E ˆ 4 1 2 πε 0 = = r r r r Q q F E ˆ 4 1 2 πε 0 = = − r r For +Q For -Q