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A 100.0 W incandescent light bulb emits about 1.6 J of energy as useful, visible light each second. What is its efficiency?

User ChesuCR
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2 Answers

6 votes

Final answer:

The efficiency of a 100.0 W incandescent light bulb emitting 1.6 J of energy as visible light each second is 1.6%.

Step-by-step explanation:

To calculate the efficiency of an incandescent light bulb, we will compare its energy output in a usable form (visible light) with the energy it consumes.

Efficiency is calculated using the formula:
Efficiency (%) = (Useful Energy Output / Total Energy Input) × 100

Here, the total energy input per second for a 100.0 W bulb is 100.0 joules (since power is the rate of energy used per second and 1 watt = 1 joule per second). The useful energy output as visible light is given as 1.6 joules per second.

So, the efficiency can be calculated as follows:
Efficiency = (1.6 J/s / 100.0 J/s) × 100 = 1.6%

Therefore, the efficiency of the light bulb in converting electrical power to visible light is 1.6%.

User Matthew Law
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4 votes

Answer:

The efficiency is just 0.016

Step-by-step explanation:

The efficiency is given by the useful energy ÷ by the total energy.

1 W is the same that 1 joule per second

If you do the math:

1.6/100=0.016

User Alisha
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