Answer:
Waste energy = Energy Input - Useful Energy Output (Principle of Energy Conservation)
Efficiency = Useful Energy Output/Energy Input (Definition of Energy Efficiency)
Explanation:
The waste energy is the difference between energy input and useful energy output. Then, the word equation is:
Waste energy = Energy Input - Useful Energy Output (Principle of Energy Conservation)
The efficiency, measured in percentage, is the ratio of the useful energy output to the energy input and multiplied by 100. Then, the word equation is:
Efficiency = Useful Energy Output/Energy Input (Definition of Energy Efficiency)