Answer to Question #77806 in Physics for Charvi

Question

If a charge +4Q is present with +2Q then how would the force be equal and opposite as electric field lines will be more of +4Q charge?

Answer 1

The electrostatic force is
F=qE.
1st case:
F_1=4QE_1=4Q k2Q/r^2 =(8kQ^2)/r^2 .
2nd case:
F_2=2QE_2=2Q k4Q/r^2 =(8kQ^2)/r^2 .
Therefore, the forces on these two charges will be equal:
F_1=F_2.