A Level Physics Practice Exam

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Study for the A Level Physics Exam. Our quiz features flashcards and multiple choice questions, each with hints and explanations. Prepare thoroughly!

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Which equation expresses the relationship between power, work, and time?

P = W / t
P = t / W
P = W * t
P = W + t

The correct answer is: P = W / t

The correct expression of the relationship between power, work, and time is represented by the equation P = W / t. This equation indicates that power (P), which is the rate at which work is done, is equal to the work done (W) divided by the time (t) taken to do that work. Power quantifies how fast work is accomplished; if more work is done in a shorter time, the power output is higher. In this context, if you calculate the work done, you can determine the power by simply dividing this work by the amount of time it took to do the work. For example, if a machine does 100 Joules of work in 5 seconds, the power output can be calculated as 100 J / 5 s = 20 Watts, illustrating the energy conversion rate of the machine. The other expressions given do not accurately reflect the definition of power in relation to work and time. They either misrepresent the relationships or do not correspond with the definitions within physics terminology.