In a certain region of space, a uniform electric field is in the x direction. A particle with negative charge is carried from x 5 20.0 cm to x 5 60.0 cm. (i) Does the electric po- tential energy of the charge-field system (a) increase, (b) re- main constant, (c) decrease, or (d) change unpredictably

(a) increase

Explanation:

On a line graph; we have the x-axis to the positive side and the negative side .In a positive x-axis direction, the force is usually positive, vice versa the negative side as well.

The change in the potential energy of a charge field-system can be given as:

where;

q = positive test charge

E = Electric field

ds = displacement between thee charge positions

θ  = Angle between the electric field and the displacement.

Given that:

Charge of the particle = -q

displacement = (60.0 -20.0)cm = 40.0 cm

θ = 0

Replacing our values in the above equation, we have:

Since the potential energy of the system is positive, therefor the electric potential energy also increases.