Efficiency Formula
The Formula
When to use: What fraction of the energy you put in actually goes where you want it to go, rather than being wasted as heat.
Quick Example
What This Formula Means
The ratio of useful output energy to total input energy, expressed as a percentage showing how little is wasted.
What fraction of the energy you put in actually goes where you want it to go, rather than being wasted as heat.
Worked Examples
Example 1
easySolution
- 1 Use the efficiency formula: \eta = \frac{\text{useful output}}{\text{total input}} \times 100\%.
- 2 Substitute the given values: \eta = \frac{350}{500} \times 100\%.
- 3 \eta = 70\%
Answer
Example 2
mediumWhy This Formula Matters
Key to understanding energy use and why we need better technology.
Frequently Asked Questions
What is the Efficiency formula?
The ratio of useful output energy to total input energy, expressed as a percentage showing how little is wasted.
How do you use the Efficiency formula?
What fraction of the energy you put in actually goes where you want it to go, rather than being wasted as heat.
Why is the Efficiency formula important in Physics?
Key to understanding energy use and why we need better technology.
What do students get wrong about Efficiency?
High efficiency doesn't mean low power use—it means less waste.
What should I learn before the Efficiency formula?
Before studying the Efficiency formula, you should understand: energy, work.