1.3.22 - Efficiency equations

Be able to use the equations useful energy output efficiency = total energy input and useful power output efficiency = total power input.

Use - efficiency equations to connect the rule to the data and decision in the question.

This matters because - efficiency equations determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - efficiency equations to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: use the formula and units given in the question, show the substitution and interpret the result; the calculation alone is not the conclusion.