Engineers who design battery-operated devices such as cell phones and MP3 players try to make them as efficient as possible. An
engineer tests a cell phone and finds that the batteries supply 10,000 J of energy to make 5500 J of output energy in the form of sound and light for the screen. How efficient is the phone?
If the pressure acting on a given sample of an ideal gas at constant temperature is tripled, the volume is reduced to one-third of its original value. <em>(a)</em>
