The alteration in potential energy is

In the query, it is stated that
The intensity of the uniform electric field equals

The distance the electron covers is 
Typically, the force exerted on this electron is expressed mathematically as
Where F signifies the force and q represents the charge of the electron, which is a fixed value of 
Thus


Generally, the work-energy theorem is mathematically framed as

Where W denotes the work done on the electron by the electric field and
is the change in kinetic energy
Additionally, work done on the electron can also be described as
Where
assuming that the electron's movement aligns with the x-axis
So

Inserting values


According to the conservation of energy
Where
signifies the change in potential energy
Thus
