Common Misconceptions

⚠️ Common Misconceptions

Misconception 1: "Watts and joules are the same thing"

Watts and joules measure different things. A joule is a unit of energy (a fixed amount of energy). A watt is a unit of power — the rate of energy transfer (joules per second). An appliance rated at 100 W transfers 100 joules every second. The longer it runs, the more total energy (joules) it uses.

Misconception 2: "Multiplying kilowatts by seconds gives kWh"

This is a very common unit error. The kWh formula requires kilowatts × hours, not kilowatts × seconds. If you're given time in seconds, either convert to hours or use E = Pt (where E is in joules, P is in watts, t is in seconds). Mixing these up will give an answer that's 3600 times too big or too small.

Misconception 3: "High voltage appliances use more energy"

Energy use depends on both voltage and current (P = IV) and on time (E = Pt). A high-voltage appliance drawing very little current may use less power than a low-voltage device drawing lots of current. It's the power rating multiplied by time used that determines the cost — not voltage alone.