Question detail
A machine has a total energy input of 500 J and produces 350 J of useful work. Calculate the efficiency of the machine.
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 machine has a total energy input of 500 J and produces 350 J of useful work. Calculate the efficiency of the machine.
Answer
0.7 or 70%
Explanation
This question assesses the ability to apply the efficiency formula in a practical context, reinforcing the concept of energy transfer. This answer is linked to Energy transfers in a system because it applies the learning objective: State that energy can be transferred usefully, stored or dissipated but cannot be created or destroyed.. It shows the Physics relationship clearly and keeps energy, power, work done and efficiency terms distinct where they appear.
Common mistake
Misunderstanding Energy Conservation
Students often think that energy can be created or destroyed in a system.
Remember that energy cannot be created or destroyed; it can only be transferred, stored, or dissipated.
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