Question detail
If a device transfers 100 joules of energy in 5 seconds, what is its power?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Energy changes in a system, and the ways energy is stored before and after such changes
Question
- A. 20 watts
- B. 25 watts
- C. 50 watts
- D. 100 watts
Answer
20 watts
Explanation
The correct option is "20 watts". 20 watts is right because it directly matches Power: Define power as the rate at which work is done.. 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
Misunderstanding Power Definition
Students often confuse power with energy, thinking it is the total energy transferred rather than the rate at which work is done.
Emphasize that power is defined as the rate at which work is done, and it is measured in watts (W), which is equivalent to joules per second.
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