What are Infrared Radiations?

            We have already that sunlight consists of all the colors seen in a rainbow. These colors ate violet, indigo, blue, green, yellow, orange and red. Light from the sun travels in the form of waves, which are known as electromagnetic waves. The human eye cannot perceive the entire band of wavelengths but can perceive those relating to these seven colors only. Rays having wavelengths higher than that of red light are called infrared rays and those lower than violet light are called ultraviolet rays. Both infrared and ultraviolet rays are not visible to our eyes. 

Infrared Rays from the Sun

            Infrared rays come not only from the sun, but also all hot objects. Infrared rays were discovered by the British astronomer sir William Herschel in 1800. burning wood and coal electric heater all produce these rays. In fact all the objects emit infrared rays depending on their temperature. Warmer objects emit more infrared rays than cooler ones. These can be recorded on special type of photographic films made of infrared sensitive materials. Whenever these rays fall on any material body they produce heat.

            Infrared radiations are used for the treatment of several diseases. Special types of infrared lamps are used for the treatment of muscle and joint aches especially back pain. They are also used for heating rooms in winters.

            Infrared radiations are used for the guidance and control of missiles and other ballistic weapons. These radiations are also used for transmitting and receiving invisible signals. Molecular structures are studied with the help of these radiations.

            These rays can also detect impurities present in materials. Infrared absorption spectroscopy is important analytical tool in organic chemistry.

What are Radio Waves?

            Radio waves are electromagnetic waves, which owe their existence to moving electrons. James clerk Maxwell first announces the existence of radio waves in 1860, but it was not until 1887 that Heinrich Hertz succeeded in generating them. Sir Oliver lodge first demonstrated wireless telegraphy in 1894, and it was Guglielmo Marconi, the Italian scientist, who could first successfully transmitted a long distance signal in 1900 with the help of radio waves.

Electromagnetic Spectrum and Diagram of Radio Transmission of an Audio Signal.

            Radio waves work as the carriers for sound communication signals. The sound signal is modulated with radio waves and transmitted with the help of a transmitter. The modulated signal is received by a radio receiver and then decoded. Radio waves transmit the signals from the broadcasting station to reach our radios. They are used to transmit a variety of programmes. Radio waves were also used to keep in contact with the flying planes and ships in high seas during World War II. With the help of these waves, they are properly guided and controlled during flights thus avoiding accidents and help in reaching their destination safely. All aircrafts and ships are equipped with radio transmitter and receivers.

            Radio waves are, in fact, invisible electromagnetic waves, which travel at the speed of light, i.e. at 300,000 kilometers per second. Satellites and spacecrafts keep in contact with earth stations with the help of these waves. Live communication with satellites and astronauts has become possible only due to radio waves. These waves can travel both through the air and vacuum. They can travel in water and underground, but the distance is restricted to a few meters. To study the radio waves originating from the different heavenly bodies, scientists make use of radio telescopes. With the help of these telescopes, it has now possible to identify planets and stars which generate radio waves.

            Police also use equipments by which they can send and receive messages while on the move. Fire brigades use radio waves while providing help in accidents. Equipments using these radio waves are used to control traffic and measure the speed of a moving vehicle from a control room.

            In a nutshell, we can say that the radio waves have shrunk the world.