Parallel network measurement — if an ideal voltmeter indicates 12 V across the source in a simple parallel circuit, what is the voltage across branch resistor R2?

Introduction / Context:
In a parallel circuit all branches share the same two nodes, so the branch voltage equals the source (node-to-node) voltage. This property simplifies measurement and analysis.

Given Data / Assumptions:

• Ideal voltmeter reads 12 V across the source terminals.
• R2 is connected in parallel across the same source nodes.
• Wiring and instruments are ideal (no wiring drop, no meter loading).

Concept / Approach:
By definition of parallel, the voltage across each branch element equals the node-to-node voltage supplied. Ohm’s law then determines each branch current independently from the common voltage and its resistance.

Step-by-Step Solution:

Verification / Alternative check:
Measure voltage across any other branch (e.g., R1). It will also read 12 V, confirming equal branch voltages in parallel.

Why Other Options Are Wrong:

Common Pitfalls:
Transferring series “voltage division” intuition to parallel networks; misplacing meter leads to unintended nodes.

Final Answer:
12 V