JEE Main 20 July 2021 Shift 1 Solved Paper

A body having specific charge 8µC∕g is resting on a frictionless plane at a distance 10cm from the wall (as shown in the figure). It starts moving towards the wall when a uniform electric field of100V∕m is applied horizontally towards the wall.
If the collision of the body with the wall is perfectly elastic, then the time period of the motion will be _____ s.