Discover a wealth of information and get your questions answered on IDNLearn.com. Join our community to receive prompt and reliable responses to your questions from experienced professionals.

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?