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Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Question 1 Page 168 An echo is heard in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m sā€“1? Speed of sound = v = 342 m/s Time taken for hearing the echo = t = 3 s Let the total distance travelled by the sound = 2d Distance of the reflecting surface from the source = Total distance / 2 = 2d/2 = d Now, Speed of sound = (š·š‘–š‘ š‘”š‘Žš‘›š‘š‘’ š‘”š‘Ÿš‘Žš‘£š‘’š‘™š‘™š‘’š‘‘ š‘š‘¦ š‘ š‘œš‘¢š‘›š‘‘)/(š‘‡š‘–š‘šš‘’ š‘‡š‘Žš‘˜š‘’š‘›) v = 2š‘‘/š‘” v Ɨ t = 2d 2d = v Ɨ t d = (š‘£ Ɨ š‘”)/2 d = (342 Ɨ 3)/2 d = 171 Ɨ 3 d = 513 m Distance between reflecting surface and source is 513 m

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo