In an introductory DC circuit, which type of circuit prevents the flow of current because the conducting path is broken?

• A. A closed circuit (switch closed)
• B. An open circuit (switch open)
• C. A series circuit with two resistors
• D. A short circuit (nearly zero resistance path)

Answer: (B)

Verified step by step guidance

1. Understand the concept of an electric circuit: it requires a complete conducting path for current to flow.
2. Recognize that a closed circuit means the switch is closed, completing the path and allowing current to flow.
3. Identify that an open circuit means the switch is open, breaking the conducting path and preventing current flow.
4. Note that a series circuit with two resistors still has a complete path, so current can flow through it.
5. Understand that a short circuit provides a path of nearly zero resistance, allowing current to flow very easily, not preventing it.