We detect electromagnetic radiation in a narrow band of frequencies that we call "visible light" with our eyes. We can feel a broader spectrum of electromagnetic radiation that we call "heat". (There are some overlaps.) We can build tools that detect ANY frequency of electromagnetic radiation, and display that in any format we select.
No. -- A fruitcake is a mixture of solids. It is not an electromagnetic wave. -- A martini is a mixture of liquids. It is not an electromagnetic wave. -- Air is a mixture of gases. It is not an electromagnetic wave. -- White light is a mixture of electromagnetic waves. -- An FM radio signal is a mixture of electromagnetic waves.
Carrier signal is of high frequencies, it gives strength to the original signal because original signal cannot travel long distances so it needs to be strengthen a bit for transmitting. The carrier signal is a high frequency signal, called an RF. Radio Frequency signal, it is to high for the human or animal ear to detect it, so its outside the audible spectrum and can easily be transmitted over the air to receivers that is…
Why are telescopes that detect different types of electromagnetic waves used to observe the universe?
Fifferent objects in the Univers have different levels of electromagnetic energy. Telescopes that detect different types of electromagnetic waves are able to see the different energy objects objects. For example night vision cameras pick up the infrared radiation of the human body that the normal cameras can't see.