Four rigid rods AB, BC CD and DA each of linear mass density and length a are rigidly to a square frame. This is placed in an XYZ space as shown in the figure. such that it can freely rotate about an Axis kk' (parallel to z-axis) The plane ABCD is on y-z plane. The rods AB and CD are carrying charges of linear charge density p and (- p)respectively. An electric field is existing in the space, which, is . If the wire frame is rotated by a small angle about the kk' axis and releaed . Find time in second required by the frame ABCD to regain its original position for the first time.
