A charged particle of mass m and charge q is released from rest in a uniform electric field E. Neglecting the effect of gravity, the kinetic energy of the charged particle after ‘t’ second is

When charge q is released in uniform electric field E then its acceleration a=qEm (is constant)So its motion will be uniformly accelerated motion and its velocity after time t is given by v=at=qEmt⇒KE=12mv2=12qEmt2=q2E2t22m