# Power, energy and efficiency

## Everything You Need in One PlaceHomework problems? Exam preparation? Trying to grasp a concept or just brushing up the basics? Our extensive help & practice library have got you covered. | ## Learn and Practice With EaseOur proven video lessons ease you through problems quickly, and you get tonnes of friendly practice on questions that trip students up on tests and finals. | ## Instant and Unlimited HelpOur personalized learning platform enables you to instantly find the exact walkthrough to your specific type of question. Activate unlimited help now! |

#### Make math click π€ and get better grades! π―Join for Free

##### Intros

##### Examples

###### Lessons

**Solving for Power and Resistance****Solving for Power, Current and Energy****Solving for Power and Voltage****Solving for Power and Efficiency**

An electric crane runs off of a 100V source at a current of 14A. The crane lifts a 180kg block 17.5m in the air (vertically) in 35 seconds. What is the efficiency of the crane?**Solving for Power and Efficiency**

A lightbulb emits approximately 300 J of light energy in 5 seconds. If this bulb is 16% efficient, what is the power supplied to the lightbulb?