Understanding Efficiency: Examples and Equations

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.

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

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