In the energy flow diagrams you have created, you will notice that quite often some energy is transformed into forms of energy that are not wanted. This energy is wasted.

For example:

In a car a lot of energy is changed into heat energy which comes out of the exhaust or from the radiator. It is wasted energy.

In a hair remover (shaver) a lot of energy is changed into sound and heat energy. This is wasted energy.

1. In each of the energy flow diagrams you drew in the last exercise indicate those forms of energy that are wasted.
2. A device is described as more efficient if less energy is changed into unwanted forms of energy. What do you think is meant by the term 'efficiency'. Give some examples.