Question

In a uniform electric field what factors does the electrical potential energy depend on

Answer 1

The electrical potential energy of a particle in a uniform electric field depends on 1) the charge of the particle 2) the distance from the source of the field 3) the magnitude of the electric field

In fact, the electrical potential energy is defined as
$U=q V$ (1)
where q is the charge and V is the voltage. Since the electric field is uniform, the voltage increase linearly with the distance from the source:
$V=Ed$ (2)
where E is the electric field strength and d is the distance. Putting (2) into (1), we find
$U=qEd$
therefore, we see that the potential energy of the particle depends on the charge q, the distance d from the source and the electric field strength E (which is constant at every location, because the field is uniform)