Defining power
- Power is defined as:
The rate of energy transfer
- Since work done is equal to the energy transferred, power can also be defined as:
Work done per unit time
- Power can be calculated using the following equations:
- Where:
- P = power in watts (W)
- E = energy in joules (J)
- W = work done in joules (J) or newton metres (N m)
- t = time in seconds (s)
- You may be familiar with power ratings on household appliances, such as 60 W or 1000 W
- These power ratings tell you the amount of energy transferred electrically from the mains supply per second