PHYS 2212 Module 3.3

Calculations of Electric Potential

Recommended Reading

3.3 Calculations of Electric Potential

Learning Objectives

By the end of this section, you will be able to:

  • Calculate the potential due to a point charge
  • Calculate the potential of a system of multiple point charges
  • Describe an electric dipole
  • Define dipole moment
  • Calculate the potential of a continuous charge distribution

Electric Potential of a Point Charge

Practice!

Practice 3.3.1
A positive charge and a negative charge are at rest with a distance of 52 cm between them.

What is the electric potential at point A?
Check your answer: A. V is a positive, non-zero value at point A
Practice 3.3.2
A positive charge and a negative charge are at rest with a distance of 52 cm between them.

What is the electric potential at point B?
Check your answer: B. V is zero at point B
Practice 3.3.3

Four point charges are arranged at the corners of a square.   Find the electric field E and the potential V at the center of the square.
Check your answer: D. E ≠ 0 V = 0

Discuss!

Reflect on this question and take notes on how you would answer it. Then we will share these thoughts together in a class discussion.

A charge of −1.0 μC is located on the y-axis 1.0 m from the origin at the coordinates (0,1) while a second charge of +1.0 μC is located on the x-axis 1.0 m from the origin at the coordinates (1,0).

Determine the value of the following quantities at the origin…

(a) the magnitude of the electric field

(b) the direction of the electric field

(c) the electric potential (assuming the potential is zero at infinite distance)

(d) the energy needed to bring a +1.0 μC charge to this position from infinitely far away