Question detail
Which device demonstrates both useful and wasted energy transfers?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Conservation and dissipation of energy
Question
- A. A bicycle powered by a human rider
- B. A solar panel converting sunlight to electricity
- C. A refrigerator keeping food cold
- D. A battery powering a flashlight
Answer
A refrigerator keeping food cold
Explanation
The correct option is "A refrigerator keeping food cold". A refrigerator keeping food cold is right because it directly matches Efficiency: Identify useful and wasted energy transfers in a device or process.. The other options are less suitable because they change the required Physics relationship, confuse the relevant energy store or use a distractor that does not answer the question.
Common mistake
Confusing useful and wasted energy
Students often label all energy moving through a device as useful, ignoring energy lost as heat or friction.
Explain that useful energy is that which performs the intended work (e.g., mechanical work, light, sound), while wasted energy is energy that leaves the system in less useful forms such as heat, sound, or vibration, and is not used for the device’s purpose.
Related flashcards
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Related practice questions
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