Efficiency Calculation of a 30 W Light Bulb

07 Aug 2023

What is the efficiency of a 30 W bulb used for one hour that produces 56000 J of light energy?

It is given that a 30 W bulb is used for one hour and produces 56000 J of light energy. Let's calculate the efficiency of the bulb.

Efficiency is the ratio of output power to input power, usually expressed as a percentage or a fraction. In this case:

Given that power of the bulb, P = 30 W

Time taken by the bulb, t = 1 hour

Energy produced by the bulb, E = 56000 J

Using the formula for power: Power, P = Energy / time

⇒ P = 56000 / (60 × 60) J/s

⇒ P = 15.56 W

Now, Efficiency (η) = (Output Power / Input Power) × 100%

Efficiency (η) = (P / P) × 100%

⇒ η = 15.56 / 30 × 100%

⇒ η = 51.87%

Therefore, the efficiency of the 30 W bulb used for one hour that produces 56000 J of light energy is 51.87%.