alleryStart learning →A resistor is connected across a fixed voltage source and its resistance is then doubled. What happens to the current?
AIt doubles in size
BIt falls to a quarter
CIt stays the same
DIt is cut in half
Answer & Solution
Correct answer: D. It is cut in half
1. Current is inversely proportional to resistance at a fixed applied voltage.
2. Writing I = V / R, doubling R with V unchanged divides I by two.
3. So the current is cut in half.
4. Falling to a quarter would need the resistance to be quadrupled, which is the usual trap of confusing this linear relation with a squared one.
_Source: OpenStax College Physics (CC BY 4.0), Ch 20 "Electric Current, Resistance, and Ohm's Law", section Resistance and Simple Circuits_
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