AP EAMCET Engineering 2018 Apr 24 Shift 1 Paper

Two charged particles each of mass 9.8 g and charges + 20 µC and - 20 µC are attached to the two ends of a massless and rigid uniform non-conducting rod of length 50 cm. This arrangement is held in a uniform electric field of 12.1 NC−1 such that the rodmakes a very small angle with the field direction. If the rod is set free, the minimum time needed for the rod to become parallel to the direction of the electric field is______ seconds.