Question

two similar stairs having + q and minus q charge are kept at a certain distance between the two if the middle of two spheres another similar sphere having plus q charges kept then its experiences force and in magnitude and direction as?
ans - 8F towards -q charge. please tell how

Answer 1

let the initial distance is d F= k qq/d2 if a third sphere is placed between then sphere having charge q repel it and sphere having charge -q attract it. force by q charged sphere =F1=k qq/(d/2)2                                                             =4k qq/d2 =4F ( from +q to -q) force by -q charged sphere =F2 =k qq/(d/2)2                                                            =4k qq/d2 =4F (from +q to -q)so net force  = 4F + 4F =8Fhope it helps