H1 Physics 8867 · objective lesson
Electrical power
Use P = VI generally and P = I²R or V²/R for a resistive component with consistent instantaneous or steady quantities.
Repair the common break
Common misconception: Electrical power is always VI only and cannot be rewritten.
Correct model: Use P = VI generally and P = I²R or V²/R for a resistive component with consistent instantaneous or steady quantities.
Worked transfer
A 6.0 Ω resistor carrying 2.0 A dissipates P = I²R = 24 W; the same operating point has V = 12 V and therefore VI = 24 W.
Guided practice
Explain why “Electrical power is always VI only and cannot be rewritten.” fails. Then construct one example that correctly applies electrical power.
Independent practice
A heater rated 230 V, 1.15 kW is resistive. Calculate its current and operating resistance.
Return to the recorded repair plan when the explanation and application are secure enough to re-test.