Answers

2016-03-10T19:43:26+05:30
Repetion of a sond by reflection of sound waves from a surface usesof an echo can be
 1 megaphones and sethoscope.
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2016-03-10T22:20:24+05:30
Echo is reflection of sound. It happens at minimum distance of 17.2 m. Uses of echo can be Sthetoscope Megaphones
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