Let's try a few more examples that relate power and energy. A certain high-efficiency LED light bulb has a power output of 9.20 W. That is, 9.20 J of electric energy is converted to electromagnetic (light) energy and radiated away every second. How much energy is output by the lightbulb if it is left on for a total time of 7.50 hours? In this case, we're relating power to energy change, so we simply use the relationship E t P = Here, instead of work W, we use in the equation E, which is the amount of energy output or converted in the amount of time t. From this, what do we find the total energy output in joules to be? 33120 x Solve the above equation for the energy E in terms of power P and time t. Remember that 1 W = 1 J/s, so to find the energy in joules, convert the time to seconds first. There are 60 minutes in one hour and 60 seconds in one minute. J

Let's try a few more examples that relate power and energy. A certain high-efficiency LED light bulb has a power output of 9.20 W. That is, 9.20 J of electric energy is converted to electromagnetic (light) energy and radiated away every second. How much energy is output by the lightbulb if it is left on for a total time of 7.50 hours? In this case, we're relating power to energy change, so we simply use the relationship E t P = Here, instead of work W, we use in the equation E, which is the amount of energy output or converted in the amount of time t. From this, what do we find the total energy output in joules to be? 33120 x Solve the above equation for the energy E in terms of power P and time t. Remember that 1 W = 1 J/s, so to find the energy in joules, convert the time to seconds first. There are 60 minutes in one hour and 60 seconds in one minute. J

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter6: Energy Of A System

Section: Chapter Questions

Problem 56P

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On December 27, 2004, astronomers observed the brightest flash of light ever recorded from outside of our solar system. It came from a highly magnetic neutron star SGR 1806-20 (also know as a magnetar). During the 0.20 s burst, this star released as much energy as our sun would over a period of 250,000 years. If our sun outputs approximately Psun = 3.846x 1026 W, what was the average power output of this magnetar in terms of Psun?
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