DC circuitsQuestion 682 of 1506

A series loop has a 45 V source and three resistors. Two of the voltage drops are 10 V and 15 V. What is the third voltage drop?

35 V
20 V
70 V
30 V

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Correct answer: 20 V

The drops must add to the source voltage: 45 V − 10 V − 15 V = 20 V.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 6.2: Kirchhoff’s Voltage Law (KVL)

Questions last reviewed: 18 October 2026

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