What is the formula for Efficiency?

• A. Efficiency = output / input x 100
• B. Efficiency = input / output x 100
• C. Efficiency = output x input / 100
• D. Efficiency = input - output

Answer: (A)

The formula for efficiency is given by the relationship between output and input, expressed as a percentage. Efficiency = (output / input) x 100 captures how effectively a system converts input energy into useful output energy. It measures the performance of an electrical system, machine, or process by comparing the useful work done (output) to the total energy supplied (input).

In practical applications, this means if you know the total energy used and the energy that is converted effectively into work or useful output, you can determine how efficient that system is. A higher efficiency indicates that a greater proportion of the input is being converted into output, which is desirable in engineering and various applications to minimize energy waste and cost.

Thus, the answer correctly reflects the standard formula for calculating efficiency in a straightforward manner.