Lesson: Power and Energy Physics • 9th Grade

In this lesson, we will learn how to use the formula P = E/t to calculate the rate at which energy is transferred by a device given the amount of energy it transfers in a given time.

Lesson Video

Sample Question Videos

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Lesson Worksheet

Q1:

A 24 W fluorescent light is left on for several hours, during which time it is supplied with 432 kJ of energy. For how many hours was the light left on?

Q2:

Which of the following is the correct unit for power?

Q3:

A 250 W television and a 400 W television are both used for two hours. How much more energy does the 400 W television require to operate for this time than the 250 W television?