Open-circuit in series — consider an ideal series circuit that develops an open in one component. Which statement best reflects the condition across the open break and the source?

Introduction / Context:
Open-circuit faults are common in connectors, fuses, and fractured solder joints. Recognizing the electrical signature of an open in a series path is critical for diagnostics. This item asks you to identify what happens to current and voltages when a series path is interrupted by an open break.

Given Data / Assumptions:

• Ideal voltage source.
• Series chain of components with one section “open” (infinite resistance).
• No alternative paths bypass the open (single path only).

Concept / Approach:
With a series open, the circuit is incomplete; therefore, current is zero everywhere in the loop: I_total = 0 A. Without current, the normal I*R drops on intact resistors disappear (each finite resistor drop is 0 V). The source still maintains its terminal voltage, and by KVL the entire source voltage appears across the open gap (the element or connection where the break occurred). This is why an open fuse often has the full supply voltage across it during operation.

Step-by-Step Solution:

Verification / Alternative check:
Measure with a voltmeter: across any intact resistor you will read ~0 V; across the open terminals you will read near the source voltage. This is the classic signature of an open series component.

Why Other Options Are Wrong:

• Current increases: Impossible without a closed loop.
• Open sees smallest drop: Incorrect; it sees the full source voltage.
• Source collapses to 0 V: Ideal sources maintain their set voltage; collapse suggests current limiting or failure, not the ideal model.

Common Pitfalls:
Confusing a short with an open; assuming all components still drop voltage despite zero current. In series, no current means no I*R drops on finite resistors.

Final Answer:
Correct — current is zero and the full source voltage appears across the open break.