Question

A point charge of 4.0 µC is placed at a distance of 0.10 m from a hard rubber rod with an electric field of 1.0 × 103 . What is the electric potential energy of the point charge?
________ × 10–4 J
What is the electric potential energy of the point charge at 1.3 m?

_________ × 10–3 J

Answer 1

4 for the first one and 5.2 for the second one.

Answer 2

E = electric field = 1 x 10³ N/C

q = charge = 4 x 10⁻⁶ C

d = distance = 0.10 m

electric potential energy is given as

U = q E d

inserting the above values

U = (4 x 10⁻⁶ ) (1 x 10³) (0.1)

U = 4 x 10⁻⁴ J

when distance = d = 1.3 m

electric potential energy is given as

U = q E d

inserting the above values

U = (4 x 10⁻⁶ ) (1 x 10³) (1.3)

U = 5.2 x 10⁻³ J