{"id":7868,"date":"2026-07-07T13:15:19","date_gmt":"2026-07-07T07:45:19","guid":{"rendered":"https:\/\/enlightify.org\/?p=7868"},"modified":"2026-07-07T13:19:47","modified_gmt":"2026-07-07T07:49:47","slug":"speed-of-sound","status":"publish","type":"post","link":"https:\/\/enlightify.org\/hi\/speed-of-sound\/","title":{"rendered":"Speed of Sound"},"content":{"rendered":"
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Speed of Sound<\/h1>\n\n

Introduction<\/h2>\n\n

\nSound travels through a medium in the form of waves. These waves move from the source of sound to the listener.\n<\/p>\n\n

\nThe speed of sound tells us how fast sound waves propagate through a medium.\n<\/p>\n\n

\nIn terms of compressions and rarefactions, speed of sound means how fast these density disturbances travel through the medium.\n<\/p>\n\n

\nSpeed of sound = Speed at which sound wave travels through a medium<\/strong>\n<\/p>\n\n

Definition of Speed of Sound<\/h2>\n\n

\nThe speed of sound is defined as the distance travelled by a point on a sound wave in unit time.\n<\/p>\n\n

\nA point on a wave may be a crest, trough, compression, or rarefaction.\n<\/p>\n\n

\nSpeed = Distance travelled by sound wave per unit time<\/strong>\n<\/p>\n\n

Formula of Speed of Sound<\/h2>\n\n

\nSpeed is given by the general formula:\n<\/p>\n\n

\n\\(v=\\frac{\\text{distance}}{\\text{time}}\\)<\/strong>\n<\/p>\n\n

\nFor a sound wave, one wavelength is the distance travelled by the wave in one time period.\n<\/p>\n\n

\nTherefore,\n<\/p>\n\n

\n\\(v=\\frac{\\lambda}{T}\\)<\/strong>\n<\/p>\n\n

\nwhere,\n<\/p>\n\n

    \n
  • \n\\(v\\)<\/strong> = Speed of sound\n<\/li>\n\n
  • \n\\(\\lambda\\)<\/strong> = Wavelength\n<\/li>\n\n
  • \n\\(T\\)<\/strong> = Time period\n<\/li>\n<\/ul>\n\n

    Relation Between Speed, Wavelength and Frequency<\/h2>\n\n

    \nWe know that frequency and time period are related as:\n<\/p>\n\n

    \n\\(\\nu=\\frac{1}{T}\\)<\/strong>\n<\/p>\n\n

    \nUsing this relation in the formula \\(v=\\frac{\\lambda}{T}\\), we get:\n<\/p>\n\n

    \n\\(v=\\lambda\\nu\\)<\/strong>\n<\/p>\n\n

    \nThus,\n<\/p>\n\n

    \nSpeed of sound = Wavelength \u00d7 Frequency<\/strong>\n<\/p>\n\n

    SI Unit of Speed of Sound<\/h2>\n\n

    \nThe SI unit of speed is metre per second.\n<\/p>\n\n

    \nSI unit of speed of sound = \\(m\\,s^{-1}\\)<\/strong>\n<\/p>\n\n

    \nIt is also written as m\/s<\/strong>.\n<\/p>\n\n

    Figure<\/h2>\n\n
    \n\n\n \n \n Speed of a Sound Wave\n <\/text>\n\n \n \n\n \n\n \n\n \n\n \n Distance<\/text>\n Density<\/text>\n\n \n \n\n Average density<\/text>\n\n \n \n\n \n Crest<\/text>\n Crest<\/text>\n\n \n \n\n \n\n \n\n \u03bb<\/text>\n One wavelength<\/text>\n\n \n \n\n \n\n \n Direction of propagation\n <\/text>\n\n \n \n\n \n v = \u03bb\u03bd\n <\/text>\n\n \n Speed = Wavelength \u00d7 Frequency\n <\/text>\n\n<\/svg>\n<\/div>\n\n

    Explanation of the Figure<\/h2>\n\n

    \nThe figure shows a graphical representation of a sound wave. The distance between two consecutive crests is one wavelength, represented by \\(\\lambda\\).\n<\/p>\n\n

    \nIf this distance is covered by the sound wave in one time period, then the speed of sound is given by:\n<\/p>\n\n

    \n\\(v=\\frac{\\lambda}{T}\\)<\/strong>\n<\/p>\n\n

    \nSince \\(\\nu=\\frac{1}{T}\\), the speed of sound can also be written as:\n<\/p>\n\n

    \n\\(v=\\lambda\\nu\\)<\/strong>\n<\/p>\n\n

    Speed of Sound in Different Media<\/h2>\n\n

    \nThe speed of sound depends on the medium through which it travels.\n<\/p>\n\n

    \nSound travels fastest in solids, slower in liquids, and slowest in gases.\n<\/p>\n\n

    \nSolids > Liquids > Gases<\/strong>\n<\/p>\n\n

    Why is Sound Faster in Solids?<\/h2>\n\n

    \nSound travels by the vibration of particles of a medium. In solids, particles are closely packed. Therefore, they can transfer vibrations quickly from one particle to another.\n<\/p>\n\n

    \nIn liquids, particles are less closely packed than solids, so sound travels slower than in solids.\n<\/p>\n\n

    \nIn gases, particles are far apart, so the transfer of disturbance is slower. Therefore, sound travels slowest in gases.\n<\/p>\n\n

    Approximate Speed Comparison<\/h2>\n\n\n\n\n\n\n\n
    Medium<\/th>\nSpeed of Sound<\/th>\nReason<\/th>\n<\/tr>\n\n
    Solids<\/td>\nFastest<\/td>\nParticles are very closely packed<\/td>\n<\/tr>\n\n
    Liquids<\/td>\nSlower than solids<\/td>\nParticles are less closely packed than solids<\/td>\n<\/tr>\n\n
    Gases<\/td>\nSlowest<\/td>\nParticles are far apart<\/td>\n<\/tr>\n\n<\/table>\n\n

    Speed of Sound in Air, Water and Steel<\/h2>\n\n

    \nThe speed of sound in air is much less than its speed in water and solids.\n<\/p>\n\n

    \nSound travels about 4 to 5 times faster in water than in air.\n<\/p>\n\n

    \nSound usually travels about 15 to 20 times faster in solids than in air.\n<\/p>\n\n\n\n\n\n\n\n
    Medium<\/th>\nApproximate Speed<\/th>\n<\/tr>\n\n
    Air<\/td>\nAbout \\(340\\,m\\,s^{-1}\\)<\/td>\n<\/tr>\n\n
    Water<\/td>\nAbout \\(1500\\,m\\,s^{-1}\\)<\/td>\n<\/tr>\n\n
    Steel<\/td>\nAbout \\(5000\\,m\\,s^{-1}\\)<\/td>\n<\/tr>\n\n<\/table>\n\n

    Speed of Sound in Air<\/h2>\n\n

    \nThe speed of sound in air depends on temperature and humidity.\n<\/p>\n\n

      \n
    • \nWhen temperature increases, the speed of sound in air increases.\n<\/li>\n\n
    • \nWhen humidity increases, the speed of sound in air also increases.\n<\/li>\n<\/ul>\n\n

      \nFor example, the speed of sound in dry air is about \\(331\\,m\\,s^{-1}\\) at \\(0^\\circ C\\), and nearly \\(344\\,m\\,s^{-1}\\) at \\(22^\\circ C\\).\n<\/p>\n\n

      \nHigher temperature or humidity \u2192 Higher speed of sound in air<\/strong>\n<\/p>\n\n

      Does Speed Depend on Frequency?<\/h2>\n\n

      \nIn most media, such as air, the speed of sound depends mainly on the medium and not on the source or the frequency.\n<\/p>\n\n

      \nIf the frequency of the source changes, the wavelength of the sound wave changes, but the speed remains almost constant in the same medium under the same conditions.\n<\/p>\n\n

      \nIn the same medium: Frequency changes \u2192 Wavelength changes, but speed remains constant<\/strong>\n<\/p>\n\n

      Relation Between Speed, Frequency and Wavelength<\/h2>\n\n

      \nThe relation \\(v=\\lambda\\nu\\) shows that speed of sound depends on wavelength and frequency.\n<\/p>\n\n

      \nIf the speed of sound is constant in a medium, then frequency and wavelength are inversely related.\n<\/p>\n\n

        \n
      • \nHigher frequency means shorter wavelength.\n<\/li>\n\n
      • \nLower frequency means longer wavelength.\n<\/li>\n<\/ul>\n\n

        Example 1<\/h2>\n\n

        \nA sound wave has wavelength \\(2\\,m\\) and frequency \\(170\\,Hz\\). Find the speed of sound.\n<\/p>\n\n

        \nGiven,\n<\/p>\n\n

          \n
        • \nWavelength, \\(\\lambda = 2\\,m\\)\n<\/li>\n\n
        • \nFrequency, \\(\\nu = 170\\,Hz\\)\n<\/li>\n<\/ul>\n\n

          \nUsing,\n<\/p>\n\n

          \n\\(v=\\lambda\\nu\\)<\/strong>\n<\/p>\n\n

          \n\\(v=2\\times170\\)<\/strong>\n<\/p>\n\n

          \n\\(v=340\\,m\\,s^{-1}\\)<\/strong>\n<\/p>\n\n

          \nTherefore, the speed of sound is \\(340\\,m\\,s^{-1}\\)<\/strong>.\n<\/p>\n\n

          Example 2<\/h2>\n\n

          \nThe speed of sound in air is \\(344\\,m\\,s^{-1}\\). If the frequency of a sound wave is \\(86\\,Hz\\), find its wavelength.\n<\/p>\n\n

          \nGiven,\n<\/p>\n\n

            \n
          • \nSpeed, \\(v = 344\\,m\\,s^{-1}\\)\n<\/li>\n\n
          • \nFrequency, \\(\\nu = 86\\,Hz\\)\n<\/li>\n<\/ul>\n\n

            \nUsing,\n<\/p>\n\n

            \n\\(v=\\lambda\\nu\\)<\/strong>\n<\/p>\n\n

            \nTherefore,\n<\/p>\n\n

            \n\\(\\lambda=\\frac{v}{\\nu}\\)<\/strong>\n<\/p>\n\n

            \n\\(\\lambda=\\frac{344}{86}\\)<\/strong>\n<\/p>\n\n

            \n\\(\\lambda=4\\,m\\)<\/strong>\n<\/p>\n\n

            \nTherefore, the wavelength of the sound wave is \\(4\\,m\\)<\/strong>.\n<\/p>\n\n

            Example 3<\/h2>\n\n

            \nA sound wave travels \\(680\\,m\\) in \\(2\\,s\\). Find its speed.\n<\/p>\n\n

            \nGiven,\n<\/p>\n\n

              \n
            • \nDistance = \\(680\\,m\\)\n<\/li>\n\n
            • \nTime = \\(2\\,s\\)\n<\/li>\n<\/ul>\n\n

              \nUsing,\n<\/p>\n\n

              \n\\(v=\\frac{\\text{distance}}{\\text{time}}\\)<\/strong>\n<\/p>\n\n

              \n\\(v=\\frac{680}{2}\\)<\/strong>\n<\/p>\n\n

              \n\\(v=340\\,m\\,s^{-1}\\)<\/strong>\n<\/p>\n\n

              \nTherefore, the speed of sound is \\(340\\,m\\,s^{-1}\\)<\/strong>.\n<\/p>\n\n

              Speed of Sound and Echo<\/h2>\n\n

              \nThe speed of sound is useful in understanding echo. An echo is heard when sound reflects from a distant surface and returns to the listener after a short time interval.\n<\/p>\n\n

              \nTo calculate distance using echo, we use:\n<\/p>\n\n

              \nDistance travelled by sound = Speed \u00d7 Time<\/strong>\n<\/p>\n\n

              \nSince sound travels to the reflecting surface and comes back, the actual distance of the reflecting surface is half of the total distance travelled by sound.\n<\/p>\n\n

              Sound and Lightning<\/h2>\n\n

              \nDuring a thunderstorm, we see lightning first and hear thunder later.\n<\/p>\n\n

              \nThis happens because light travels much faster than sound. Sound takes more time to reach our ears.\n<\/p>\n\n

              \nThis delay helps us understand that sound has a finite speed.\n<\/p>\n\n

              Examples from Daily Life<\/h2>\n\n
                \n
              • \nWe hear thunder after seeing lightning because sound travels slower than light.\n<\/li>\n\n
              • \nSound reaches faster through railway tracks than through air.\n<\/li>\n\n
              • \nA person can hear knocking through a steel fence before hearing the same sound through air.\n<\/li>\n\n
              • \nSound travels faster in water than in air.\n<\/li>\n\n
              • \nThe speed of sound increases in warmer air.\n<\/li>\n<\/ul>\n\n

                Important Terms<\/h2>\n\n

                1. Speed of Sound<\/h3>\n\n

                \nThe distance travelled by a sound wave in unit time.\n<\/p>\n\n

                2. Wavelength<\/h3>\n\n

                \nThe distance between two consecutive crests or two consecutive troughs of a wave.\n<\/p>\n\n

                3. Frequency<\/h3>\n\n

                \nThe number of complete oscillations per unit time.\n<\/p>\n\n

                4. Time Period<\/h3>\n\n

                \nThe time taken to complete one oscillation.\n<\/p>\n\n

                5. Medium<\/h3>\n\n

                \nThe material through which sound propagates.\n<\/p>\n\n

                Important Points<\/h2>\n\n
                  \n
                • \nThe speed of sound tells how fast sound waves propagate through a medium.\n<\/li>\n\n
                • \nSpeed of sound is the distance travelled by a point on a sound wave in unit time.\n<\/li>\n\n
                • \nThe general formula of speed is \\(v=\\frac{\\text{distance}}{\\text{time}}\\).\n<\/li>\n\n
                • \nFor a sound wave, \\(v=\\frac{\\lambda}{T}\\).\n<\/li>\n\n
                • \nThe relation between speed, wavelength and frequency is \\(v=\\lambda\\nu\\).\n<\/li>\n\n
                • \nThe SI unit of speed of sound is \\(m\\,s^{-1}\\).\n<\/li>\n\n
                • \nSound travels fastest in solids, slower in liquids, and slowest in gases.\n<\/li>\n\n
                • \nSpeed of sound in air increases with temperature.\n<\/li>\n\n
                • \nSpeed of sound in air also increases with humidity.\n<\/li>\n\n
                • \nIn the same medium, speed of sound remains almost constant even if frequency changes.\n<\/li>\n<\/ul>\n\n

                  Conclusion<\/h2>\n\n

                  \nThe speed of sound describes how fast sound waves travel through a medium. It is defined as the distance travelled by a point on a sound wave in unit time. The speed of sound is related to wavelength and frequency by the formula \\(v=\\lambda\\nu\\)<\/strong>. Sound travels fastest in solids, slower in liquids, and slowest in gases. In air, the speed of sound increases with temperature and humidity. In most media, the speed of sound depends on the medium, not on the frequency of the source.\n<\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"

                  Speed of Sound Introduction Sound travels through a medium in the form of waves. These waves move from the source of sound to the listener. The speed of sound tells us how fast sound waves propagate through a medium. In terms of compressions and rarefactions, speed of sound means how fast these density disturbances travel […]<\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[98],"tags":[],"class_list":["post-7868","post","type-post","status-publish","format-standard","hentry","category-physics"],"_links":{"self":[{"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/posts\/7868","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/comments?post=7868"}],"version-history":[{"count":4,"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/posts\/7868\/revisions"}],"predecessor-version":[{"id":7874,"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/posts\/7868\/revisions\/7874"}],"wp:attachment":[{"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/media?parent=7868"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/categories?post=7868"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/enlightify.org\/hi\/wp-json\/wp\/v2\/tags?post=7868"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}