Parallel branch voltage check: If a resistor R3 is connected directly in parallel with an ideal 20 V DC source (i.e., across the same two supply nodes), the voltage across R3 should be 20 V. Decide if this statement is valid.

Introduction / Context:
Parallel elements share the same voltage because they are connected to the same two nodes. Recognizing this is essential for determining branch currents with Ohm’s law and for verifying measurements made with a voltmeter in complex series–parallel circuits.

Given Data / Assumptions:

• Ideal 20 V DC source.
• Resistor R3 is connected directly across the source terminals (true parallel).
• Negligible lead/wiring resistance and no intervening elements.

Concept / Approach:
By definition of parallel connection, the voltage across each parallel branch equals the source voltage. The resistor’s value affects current (I = V/R) but not the branch voltage in the ideal model. Therefore, any component in parallel with the 20 V source experiences 20 V across it.

Step-by-Step Solution:

Verification / Alternative check:
Measure with a high-impedance DMM across R3: the reading matches the supply voltage, verifying the rule in practice barring notable wiring drops.

Why Other Options Are Wrong:

• Incorrect / depends on current / valid only for analog meters: Voltage in parallel is independent of resistor value and meter type in the ideal case.
• True only when R3 = 20 Ω: Resistance value does not set branch voltage in parallel.

Common Pitfalls:
Confusing series voltage division with parallel voltage equality; inserting a meter incorrectly and loading the circuit, which could change a non-ideal reading.

Final Answer:
Correct