Energy Transfer and Efficiency _ GCSE Physics

The video tutorial explains how energy is transferred in systems like car engines and lamps, highlighting that not all input energy is converted into useful energy. It introduces Sankey diagrams to visualize energy transfers and discusses the inefficiency of energy conversion, particularly in electric lamps. The tutorial concludes with a formula to calculate efficiency, using an example where only 10% of energy is useful.

What does it indicate if most of the electrical energy in a lamp is transferred as heat?

How can we calculate the efficiency of an energy transfer process?