Which of the following loads would require the most electrical power in a given setup?

Which of the following loads would require the most electrical power in a given setup?

• A. Two lights requiring 3 amperes each in a 24-volt parallel system
• B. One motor drawing 4 amperes at 24 volts
• C. One heating element drawing 5 amperes at 24 volts
• D. Two lights drawing 2.5 amperes each at 24 volts

Answer: (A)

Power in a circuit is equal to voltage times current, P = V × I. In a 24-volt system, every load draws power based on its own current: P = 24 × I. When loads are in parallel, they all see the same voltage, so you compare by their currents, and the total power is the sum of each load’s power. Two lights drawing 3 A each use 24 × 3 = 72 W per light, so together they draw 144 W. That is higher than the motor at 4 A (96 W), the heating element at 5 A (120 W), or the two lights at 2.5 A each (60 W each, totaling 120 W). Hence this arrangement requires the most electrical power.

Power in a circuit is equal to voltage times current, P = V × I. In a 24-volt system, every load draws power based on its own current: P = 24 × I. When loads are in parallel, they all see the same voltage, so you compare by their currents, and the total power is the sum of each load’s power.

Two lights drawing 3 A each use 24 × 3 = 72 W per light, so together they draw 144 W. That is higher than the motor at 4 A (96 W), the heating element at 5 A (120 W), or the two lights at 2.5 A each (60 W each, totaling 120 W). Hence this arrangement requires the most electrical power.