Red Seal Electrician Practice
Meters and troubleshootingQuestion 652 of 1506

In a series circuit one resistor fails open. A voltmeter across that resistor reads the full supply voltage. What do the other resistors show?

  1. A higher voltage drop than before the fault
  2. The same voltage drop as before the fault
  3. Half of the supply voltage each
  4. No voltage drop, because the circuit current is zero
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Correct answer: No voltage drop, because the circuit current is zero

An open part in series stops all the current. With no current, there is no drop across the good resistors.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 5.7: Component Failure Analysis

Practice meters and troubleshooting

Questions last reviewed: 18 October 2026