(Optional) Compare potential and electromotive forces.

Comparison should include

• potential energy—the difference between the energy of an object in a given position and its energy at a reference position
• electromotive force (EMF)—considered a potential difference of a source when no current is flowing and refers to voltage generated by a battery or by a magnetic force, according to Faraday's law.

Process/Skill Questions:

• How is potential energy measured?
• What is the difference between EMF and voltage?
• What factors affect potential energy?