Question detail

If a device transfers 100 joules of energy in 5 seconds, what is its power rating?

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

20 watts

Power is calculated as energy transferred divided by time. Here, power = 100 joules / 5 seconds = 20 watts.

Confusing Power and Energy

Students often confuse power (watts) with energy (joules), thinking they are the same.

Remember that power is the rate at which energy is transferred, defined as 1 watt being equivalent to 1 joule per second.

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