LEARNATHON
III

Competition for grade 6 to 10 students! Learn, solve tests and earn prizes!

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Theory:

Sound travels at a finite speed through a medium. The sound of thunder arrives a few seconds after the flash of light. As a result, we can deduce that sound travels at a much slower rate than light. The properties of the medium through which sound travels determine its speed. In a gaseous medium, sound travels slower than in a solid medium. When the temperature of a medium is increased, the speed of sound increases. The speed of sound in air, for example, is \(330\) m/s at \(0\) \(°C\) and \(340\) m/s at \(25\) \(°C\).
 
table3.jpg
The above table shows the sound speed in various media at \(25\)\(° C\).
 
When an object travels faster than the speed of sound in the air, it is said to be travelling supersonically. Bullets, jets, and planes, among other things, can travel at supersonic speeds. Shock waves are created when an object travels faster than the speed of sound in the air; these shock waves carry a large amount of energy, and the air pressure variations associated with this type of shock wave produce a very sharp and loud sound known as 'sonic boom.' An aircraft's shock waves have enough energy to shatter glass and even damage buildings.
 
Sound travels about five times faster in water than in air. Since the speed of sound in seawater is very large (being about \(1530\) m/s, which is more than \(5500\) \(km/h\)), two whales in the sea, which are even hundreds of kilometres away, can talk to each other very easily through the seawater.