Skip to main content

Learning Introductory Physics with Activities

Paul J. Emigh, Rebecka Tumblin, Kathryn Hadley, Danielle Skinner

Section 26.3 Ideal Batteries and Wires

Subsubsection Key Ideas

🔗
Essential to analyzing circuits is to have a model for the voltage across each possible circuit element, starting with ideal batteries and ideal wires.
🔗

Definition 26.3.2. Battery.

A battery is a circuit element that provides a source of voltage.
🔗
  • There is a voltage difference between the terminals of a battery. The \(+\) terminal of the battery is at a higher voltage than the \(-\) terminal.
    🔗
    🔗
  • A battery stores chemical potential energy. When the battery is part of a complete circuit, the chemical energy is converted to electric potential energy by separating charged ions in a chemical solution.
    🔗
    🔗
  • The separated ions create an electric field. When the battery is part of a complete circuit, an electric field exists in both the battery and in the conductors that make up the circuit. These conductors are thus not in electrostatic equilibrium.
    🔗
    🔗
A circuit diagram with a stylized representation of a battery on the left and a conducting wire on the right. The battery has positive charges along its top and negative charges along its bottom, with downward vectors representing the electric field inside. The conducting wire has charges along its side, with downward vectors representing the electric field inside.
Figure 26.3.3. Example: simplified charge diagram and electric field vectors for a battery (left) connected in a complete circuit to a conducting wire (right). The charges in the battery represent ions that have moved as a result of a chemical reaction occurring inside the battery; the charges on the wire result from electrons moving in response to the voltage provided by the battery. The resulting electric field inside the conducting wire forces current to move.
🔗
🔗

Subsubsection Activities

Activity 26.3.1. Properties of Ideal Batteries and Wires.

Which of the following statements are true?
🔗
  • When the battery is in a complete circuit, it is in electrostatic equilibrium
    🔗
    🔗
  • The positive terminal of the battery is at a higher voltage than the negative terminal of the battery
    🔗
    🔗
  • The negative terminal of the battery always has a voltage equal to zero
    🔗
    🔗
  • The voltage across an ideal wire is equal to zero
    🔗
    🔗
🔗
🔗
🔗
PrevTopNext