If voltage doubles and resistance remains constant, how does current change?

• A. It decreases by half.
• B. It doubles.
• C. It remains the same.
• D. It quadruples.

Answer: (B)

Current responds directly to voltage when resistance doesn’t change, as described by Ohm’s law I = V / R. If you double the voltage while keeping the resistance constant, the current must double because you’re pushing twice as much voltage across the same obstacle. For example, with V = 10 V and R = 5 Ω, I = 2 A; doubling the voltage to 20 V gives I = 4 A. So the current doubles. The other options don’t fit this relationship: halving, staying the same, or quadrupling would require different changes in voltage or resistance that aren’t present in this scenario.