Answer:

Explanation:
Initial speed of the electron, u = 0
The charge per unit area of each plate, 
Separation between the plates, 
An electron is released from rest, u = 0
Using equation of kinematics,
..........(1)
Acceleration of the electron in electric field,
............(2)
Electric field,
............(3)
From equation (1), (2) and (3) :


v = 10840393.1799 m/s
or

So, the electron is moving with a speed of
before it reaches the positive plate. Hence, this is the required solution.