Energy efficiency in physics is not measured the way most people think about it. Instead of asking how much heat a process produces per unit of fuel, physicists often compare how much of a substance’s ...

Lowry Kirkby reviews The Theoretical Minimum: What You Need to Know to Start Doing Physics by Leonard Susskind and George Hrabovsky Thirst for physics: Leonard Susskind's popular series of lectures ...

A very inefficient device will waste most of its input energy. The efficiency of a device is the proportion of the energy supplied that is transferred in useful ways. The efficiency can be calculated ...