Question detail
A light bulb uses 60 J of electrical energy and produces 10 J of light energy. Calculate the efficiency of the light bulb.
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Conservation and dissipation of energy
Question
A light bulb uses 60 J of electrical energy and produces 10 J of light energy. Calculate the efficiency of the light bulb.
Answer
0.1667 or 16.67%
Explanation
This question tests the ability to calculate efficiency, which is a measure of how much input energy is converted into useful output energy. This answer is linked to Efficiency because it applies the learning objective: Calculate efficiency using useful energy output divided by total energy input.. It shows the Physics relationship clearly and keeps energy, power, work done and efficiency terms distinct where they appear.
Common mistake
Confusing Efficiency Calculation
Students often confuse the formula for efficiency by using total energy output instead of useful energy output.
Remember to use the formula: efficiency = useful energy output / total energy input.
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