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JEE Main202120 Jul 2021Morning ShiftPhysicsCenter of Mass, Momentum and CollisionActual

A body having specific charge 8   μC   g - 1 is resting on a frictionless plane at a distance 10   cm from the wall (as shown in the figure). It starts moving towards the wall when a uniform electric field of 100   V   m - 1 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 .

Correct answer

1

Step-by-step solution

F = m a q E = m a a = q E m Now d = 1 2 a t 2 t = 2   d a t = 2   d q E m t = 2 × 0 . 1 8 × 10 - 6 10 - 3 × 100 = 1 2 ∴ Time period = 2 t = 1   s Answer = 1 . 00

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