Question

3. A lightbulb 500 J of energy is transferred to a lightbulb. 350 J is transferred as heat. The rest is transferred as light. Calculate the efficiency of the bulb.​

Answer 1

The efficiency of a bulb can be calculated as the ratio of the useful energy output (in this case, the light energy) to the total energy input. In this scenario, the useful energy output is 500 J - 350 J = 150 J, and the total energy input is 500 J. So, the efficiency can be calculated as:

Efficiency = (useful energy output) / (total energy input) = (150 J) / (500 J) = 0.3 or 30%.

This means that 30% of the energy input was converted into useful light energy, while 70% was converted into heat. This is the efficiency of the bulb.