GCSE Physics: EfficiencyThe efficiency of an electrical appliance is given by the equation:
Efficiency = (Useful energy output / Total energy input) * 100
Some of the energy is lost to the environment surrounding the appliance and we say it is dissipated.
A lightbulb uses 150kJ energy. 100kL are transferredto heat, and therest to light. What is the efficiency?
Efficiency = (Useful energy output/Total energy input) * 100
= ((150-100)/150) * 100