What is the formula for efficiency?

The formula for efficiency is commonly defined as the ratio of useful work output to the total work input, expressed as a percentage. The correct choice presents this relationship as "Efficiency = Work output on Work input," which clearly articulates the concept.

In the context of engineering and physics, efficiency is an essential measure for evaluating the performance of machines and systems. It indicates how effectively a system converts input energy, power, or work into useful output without unnecessary losses (such as friction, heat, etc.). Efficiency can be represented mathematically as:

Efficiency = (Useful output work / Total input work) × 100%

This equation highlights that efficiency is a dimensionless quantity expressed as a percentage, allowing for easy comparison among different systems or machines.

The other options provided do not accurately describe efficiency in the context of work or energy conversion. For instance, some involve mechanical advantage and velocity ratio, which relate more to the performance of machines rather than directly calculating efficiency. Understanding the correct formula for efficiency is crucial in evaluating the effectiveness of engineering designs and technologies.