Question

a 2 microcoulomb charge exert a force of (7i^ - 24 j^)N on another charge of 4 microcoulomb. find the force exerted by 4 microcoulomb charge on 2 microcoulomb

Answer 1

Coulomb's law obeys Newton's 3rd law. I mean, if two charged particle q1 and q2 are seperated r apart. then force exerted by q1 on q2 = - force exerted by q2 on q1. [ that's why it obeys Newton's 3rd law, according to this law “ action and reaction are of equal in magnitude but directed in opposite directions ” ].

given, force exerted by 2uC charge on 4uC = (7i - 24 j) N

so, force exerted by 4uC charge on 4uC = -force exerted by 2uC charge on 4uC

= -(7i - 24j) N

= (-7i + 24j) N

hence, required answer is (-7i + 24j) N