Question

Using the law of conservation of energy, explain why an LED light is more energy efficient that an incandescent light bulb.

Answer 1

An LED light uses one-third the energy of an incandescent bulb to produce the same amount of light.

Step-by-step explanation:

A typical 100 W incandescent bulb produces about 5 % visible light, 83 % IR radiation, and 12 % heat (it is the IR radiation that makes the bulb feel hot).

It produces about 5 J of light energy for every 100 J of energy input.

A typical LED bulb produces about 15 % visible light and 85 % heat (LEDs feel cool, because they don't produce IR radiation).

It produces about 15 J of light energy for every 100 J of energy input.

Thus, an LED light is about three times as efficient at converting electrical energy into light