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. 50 watts
- C. 100 watts
- D. 200 watts
Answer
20 watts
Explanation
The correct option is "20 watts". 20 watts is right because it directly matches Power: Explain why two devices can transfer the same amount of energy but have different powers if one transfers it faster.. 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
Students often think that power is the total amount of energy transferred, rather than the rate at which energy is transferred.
Emphasize that power is defined as the rate of energy transfer, and clarify that two devices can transfer the same energy but have different power ratings based on how quickly they do so.
Related flashcards
Flashcard 1 of 5
Related practice questions
Question 1 of 5
Choose an answer, get feedback, then move sideways through the set.