PROPERTIES OF ELECTROMAGNETIC WAVES: In our previous session we have learnt about types of electromagnetic spectrum.We have learnt the common features among radiations of electromagnetic spectrum.Now let us learn the properties of different radiations.The wavelength of the radiation of visible spectrum extends from 0.4 um-0.7um.The colors of radiation are from violet color to red color.During transition of electrons, the color of the light emitted is the characteristic of atom of that particular substance.The wavelength of the infrared radiations is longer than visible light.It extends from 0.7um to 100 um.Heat travels in the form of infrared radiations from the hot body, hence hot bodies forms as source of infrared radiations.Micro waves are produced by high frequency electromagnetic oscillators in electric circuits.The wavelength of microwaves extends from 10um to 10 m.Radio waves are produced by low frequencyelectromagnetic oscillators in electric circuits.The wavelengths of radio waves extend from 1m to 100 km. These waves can travel long distances and also these can be received from long distances like extra-terrestrial sources.Ultra violet radiations are with shorter wavelength than visible light.The wavelength of UV radiations is 0.4 um to 1nm.These radiations are harmful to human bodies, and long term exposure leads to skin cancer.The wavelength of x-rays extends from 0.001nm to 10 nm or 0.001A0 to 100A0. The spacing between the atoms in a crystalline solid from 0.1 A0 to 10 A0.Gamma rays are electromagnetic radiations with shorter wavelengths ranges from 0.0001nm to 0.1nm or from 0.001A0 to 1 A0.Natural radioactive substances like Uranium 235emit gamma radiations.Gamma radiations are most penetrating electromagnetic radiations produced in the decay of certain of elementary particles.

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