In a closed circuit:

• A. No current flows
• B. The circuit generates negative voltage
• C. The device fails to operate
• D. Electrons flow in a complete uninterrupted path

Answer: (D)

In a closed circuit, there is a complete, uninterrupted path for current to flow. The power source creates a potential difference that pushes charges around the loop, so electrons move continuously from one terminal, through conductors and any devices, back to the source. If the loop is broken, current stops, which is why an open circuit has no current. The idea of a “negative voltage” isn’t what defines a closed circuit, since polarity depends on the source and reference, not on the loop being closed. And while a closed loop allows current to reach a device, whether the device operates depends on other factors as well; the fundamental point is that current can flow through a complete loop.