Electromagnetic Spectrum

    The first part of electromagnetic spectrum to be discovered is infrared radiation, by William Herschel in 1800. Fig. Discoveries of EM waves yearwise    Later Next year, Johann Ritter , noticed chemical rays behaving similarly to visible violet rays which are named as ultraviolet rays. Michael Faraday in 1845 first linked electromagnetic radiation with electromagnetism. He noticed that the polarized light travelling through a transparent material responds to a magnetic field, which is called as Faraday effect.         In 1860, James Maxwell developed 4 partial differential equations for electromagnetic field, by these he realized that waves must travel at speed that was about the speed of light. Wilhelm Rontgen in 1895 noticed a new type of radiation which is emitted during an experiment with an evacuated tube which subjected  to a high voltage. He called these radiation as X-Rays .      In 1900, Paul Villard ...

 Electromagnetic waves are associated with following physical properties: i) frequency ii) wavelength iii) Amplitude iv) Intensity Actually Electromagnetic spectrum is ordered according to frequency and wavelength.  1) Frequency :      Frequency is the number of occurence of a particular event per un it time. Here the number of cycles of waves per unit time is the frequency of the wave.         The unit of frequency is Hertz (Hz) which is equal to unit occurence of a repeating event per second.  2) Wavelength :      It is the distance between identical points or adjacent crest or trough of a waveform signal.  It is usually measured in metres(m).  3) Amplitude :   It is maximum displacement or distance moved by point on vibrating body from its equilibrium position.  It is also measure in metre.  4) Intensity : Here, Intensity is the strength of wave. It is also synonymous with amplitude, mag...

  El ectromagnetic radiation  refers to the waves  of the electromagnetic field  radiating through space, carrying electromagnetic  r adiant energy . It consists of radio waves, microwaves, infrared, visible light, uv light, X rays, and gamma rays.  Fig. Electromagnetic wave 1)Electromagnetic waves are produced by electrically charged particles that are undergoing acceleration and these waves can interact with another charged particles, exerting force on them itself.  2) EM waves carry energy, momentum as well as angular momentum away from their source particle . 3) Electromagnetic radiations are associated with those EM waves that are free to radiate themselves without the  influence of the moving charges that produced them, because they have achieved minimum distance from those charges.  4) Thus ,a wave carrying energy of charged particles forms a radiation. 

 The radiations in electromagnetic spectrum are as follows: 1.Gamma radiation 2.X-ray radiation 3.Ultraviolet radiation 4.Visible light 5.Infrared radiation 6.Microwave radiation 7.Radio waves The frequency and wavelength range for different types of radiation can be cleared with the help of above diagram. 

  1) Radio Waves: These  are at  lowest range of the electromagnetic spectrum having frequencies of up to 30 billion Hz i.e 30 GHz, and have wavelengths greater than about 10 mm or 0.4 inches. Radio is used mainly for communications of data, voice and entertainment media. 2) Microwaves: These waves fall in range of the Electromagnetic spectrum  between radio and Infrared. They have frequency range from about 3 GHz to 30 trillion hertz, or 30 terahertz (THz), and wavelengths of  10 mm (0.4 inches) to 100 micrometers (μm), or 0.004 inches. They are used for high-bandwidth communications like radar and for heat source of microwave ovens also for some industrial applications. 3) Infrared: Infrared waves lies in the range of the EM spectrum between microwaves and visible light. They have frequency range  from about 30 THz up to about 400 THz and wavelengths of range 100 μm (0.004 inches) to 740 nanometers (nm), or 0.00003 inches. This light is invisible to human...

  Gamma rays are primarily used for killing the bacteria and other microinsects in marshmallows &for sanitizing medical equipment X-rays are basically used for scanning the structures of bone images.  Ultraviolet light can be used to observe bees because flowers can stand-out visibly at the  frequency range of uv light Visible light is most important because it is used to view the world by humans Infrared light is used in laser metal cutting, night vision, and heat sensors and many more such appliances.  Microwave is used in radar, sonar techniques and specially in microwave ovens Radio waves are primarily used in radio, TV broadcasting.