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Light and Sound

'Light' travels in vaccum but not 'sound' - Why?
Sound is a 'mechanical wave' where as light is an electromagnetic wave. Mechanical waves propagate through the vibrations of material particles which are physically present. Sound energy propagates in the form of a mechanical wave through solids, liquids and gases when their particles vibrate; the energy transfers from particle to particle. Thus for sound to travel there is a necessity for a material medium.
when electric charges vibrate, electric and magnetic fields develop around them. These two fields will be making oscillations in planes perpendicular to each other. Because of these oscillations, electro magnetic waves like 'Light' are produced which does not need a material medium to propagate thus light travels through vaccum.
Not only the light which is visible to our eyes, but also the invisible infrared, ultraviolet rays, radio waves, X-rays, gamma rays are electromagnetic waves. For the propagation of the above rays no material medium is required and thus they can propaget through vaccum.
Published date : 06 Jul 2013 01:20PM

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