Which expression represents the power in terms of voltage and current?

Which expression represents the power in terms of voltage and current?

• A. Power = current / voltage
• B. Power = voltage drop
• C. Power = voltage x current
• D. Power = voltage + current

Answer: (C)

Power is the rate at which electrical energy is transferred, and it depends on both how much pushing force exists (voltage) and how much charge actually flows (current). The expression P = V × I captures this directly: power in watts equals voltage in volts times current in amperes. This aligns with the idea that higher voltage pushes more charge per second and higher current means more charge moving per second, so their product represents energy transfer per unit time. For example, a 12-volt source with 2 amperes of current delivers 24 watts. The other forms don’t describe energy transfer correctly: dividing current by voltage isn’t power, a voltage drop is just a potential difference across a component, and adding voltage and current combines unlike quantities. Note that in AC circuits with phase differences, real power is P = V_rms × I_rms × cosφ, but the basic relationship for instantaneous power remains the product of voltage and current.

Power is the rate at which electrical energy is transferred, and it depends on both how much pushing force exists (voltage) and how much charge actually flows (current). The expression P = V × I captures this directly: power in watts equals voltage in volts times current in amperes. This aligns with the idea that higher voltage pushes more charge per second and higher current means more charge moving per second, so their product represents energy transfer per unit time. For example, a 12-volt source with 2 amperes of current delivers 24 watts. The other forms don’t describe energy transfer correctly: dividing current by voltage isn’t power, a voltage drop is just a potential difference across a component, and adding voltage and current combines unlike quantities. Note that in AC circuits with phase differences, real power is P = V_rms × I_rms × cosφ, but the basic relationship for instantaneous power remains the product of voltage and current.