Work and electric potential in a field

[rrr3221]

Homework Statement

if the electric field does negative work on a negative charge as the charge undergoes displacement from Position A to Position B within an electric field, then the electric potential energy

A) is negative
B) is positive
C) increases
D) decreases
E) cannot be determined

Homework Equations

u=qed, v=qu, v=ed

The Attempt at a Solution

since both q and u are negative V must be positive

 

[rl.bhat]

Within an electric field the electric potential is always positive. As you change the position it either increases or decreases. If you move in the direction of the field it decreases.

 

[nlightner]

. Additionally, since the electric field is doing negative work, the electric potential energy must be decreasing as the charge moves from Position A to Position B. Therefore, the correct answer is D) decreases.

I would like to add that the electric potential energy is a scalar quantity and its sign depends on the direction of the electric field and the charge. In this case, the electric field and charge are both negative, so the electric potential energy is positive. However, if the charge was positive, the electric potential energy would be negative in this scenario. It is important to consider the direction of the electric field and the charge when determining the sign of the electric potential energy. Additionally, the electric potential energy is related to the work done by the electric field on the charge, but it is not the same as work. Work is a vector quantity and takes into account the displacement and the force acting on the charge, while electric potential energy only considers the charge and the electric field.