ryshckf74

Well Because of the different type of energy used in radar and sonar, each has its own applications. The word "radar" was formed from the first letters of the term "radio detection and ranging." A radio wave is a type of electromagnetic radiation. (Microwaves, X-rays, and light waves are other types.

AL2006

Microwave ovens are often used to cook the food in the first place, but that's not what I think this question is referring to.

In some restaurants, you'll often see a certain shelf between the kitchen and the dining area, where the cooks put the plates that are waiting to be picked up by the waiters. There are usually a row of lights over this shelf, that shine on the plates to keep the food warm. Those are " infrared " lights. When I was growing up, they were also called "heat lamps".

The thing about them is this ... if you want to look at it this way: They're light bulbs that are designed and built to have extra-LOW efficiency. Of the total electrical energy that one of these bulbs uses, only a SMALL amount of it becomes light energy, and a LARGE amount of it becomes heat energy.