When you listen to the radio, watch TV, or cook dinner in a microwave oven, you are using electromagnetic waves.
Radio waves, television waves, and microwaves are all types of electromagnetic waves. They differ from each other in wavelength. Wavelength is the distance between one wave crest to the next.
Waves in the electromagnetic spectrum vary in size from very long radio waves the size of buildings, to very short gamma-rays smaller than the size of the nucleus of an atom.
* Some uses for Radio Waves and Micorwaves?
Radio waves are the lowest-energy, lowest-frequency and longest-wavelength electromagnetic waves. They are produced when an alternating current flows in an aerial and they spread out and travel through the atmosphere. They are not strongly absorbed by the atmosphere. Another aerial is used as a detector and the waves produce an alternating current in it, with a frequency that matches that of the radio waves. Anyone with a receiver can tune it to this frequency to pick up the radio waves so they are suitable for broadcasting (for example, radio and TV programmes) to large numbers of people. An advantage is that this method of communicating does not require wires to transmit information. A disadvantage is that radio stations using similar transmission frequencies sometimes interfere.
A common mistake is to think that we can hear radio waves. We cannot hear any electromagnetic radiation. The radiation is used to carry a signal that is converted into a sound wave by the receiver.
Medium wavelength radio waves are reflected from the ionosphere, a layer of charged particles in the upper atmosphere, so they can be used for long distance communication.
* Examples of how infared waves and visible light are important in our life?
Infrared (IR) is a form of electromagnetic radiation that has a wavelength slightly longer than the color red in the visible light spectrum. Infrared radiation is created when objects are heated at temperatures not quite high enough to make them glow. You can detect infrared radiation by the heating effect it has on your skin. Special sensors are also used to detect IR. This type of radiation is used in electric heaters, greenhouses and night vision sensors
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