Understanding Efficiency: Examples and Equations

Understanding Efficiency: Examples and Equations

Assessment

Interactive Video

Physics, Science, Engineering

10th Grade - University

Hard

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The video tutorial explains how devices transfer energy and the concept of efficiency, which is the percentage of input energy that is usefully transferred. It provides three examples: a light bulb, a speaker, and an electric motor, illustrating how to calculate efficiency using different forms of energy. The light bulb transfers only 8% of its energy as light, the speaker converts 48% into sound, and the electric motor has a 5.2% efficiency in lifting a mass. The remaining energy in each case is wasted as thermal energy.

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2 questions

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1.

OPEN ENDED QUESTION

3 mins • 1 pt

What is the efficiency of the speaker that uses 500 watts of electrical energy to produce 240 watts of sound energy?

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2.

OPEN ENDED QUESTION

3 mins • 1 pt

Describe the process of calculating the efficiency of the electric motor lifting a mass.

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