Physics
Power Efficiency
Quick fact
A typical incandescent light bulb has a power efficiency of about 2-3%, while an LED bulb can exceed 50% efficiency.
Why this is interesting
You flip a switch and a light bulb glows, but did you know that over 90% of the electricity it uses is wasted as heat, not light? Why do some devices convert almost all their power into useful work while others lose most of it?