Newton’s all three laws of motion are very important for the questions in which objects falling from a particular height for a particular time

A force is generated because of the elective field

F=qE

⇒ a = qE/m.

As the particle starts from rest and acceleration is constant applying equation of motion.

V = u + at

V = 0 + qEt/m

V = qEt/m

Hence, a charged particle of mass m and charge q is released from rest in an electric field of uniform strength E. The kinetic energy of the particle after a time t will be

Then, KE 1/2mv2 = 1/2m(qEt/m)2

q2E2t2/2m