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In applying Kirchhoff's Voltage Law, why are some voltages taken as positive and others as negative?
ABecause larger voltages are always positive and smaller ones are always negative.
BBecause the sign depends on the direction of loop traversal relative to the indicated polarity of each element.
CBecause source voltages are always negative and resistor voltages are always positive.
DBecause alternating voltages must be negative in a loop equation.
Answer & Solution
Correct answer: B. Because the sign depends on the direction of loop traversal relative to the indicated polarity of each element.
The sign in a KVL equation depends on how you traverse the loop. Crossing an element from negative to positive terminal is a rise, while crossing from positive to negative is a drop. The sign is therefore determined by traversal direction and marked polarity, not by the component type alone.