# Example 12.1 - Chapter 12 Class 9 - Sound

Last updated at June 26, 2019 by Teachoo

Last updated at June 26, 2019 by Teachoo

Transcript

Example 12.1 A sound wave has a frequency of 2 kHz and wave length 35 cm. How long will it take to travel 1.5 km? Frequency of sound = f = 2 kHz = 2000 Hz Wavelength = ๐ = 35 cm = 35/100 m = 0.35 m Distance travelled = d = 1.5 km = 1.5 km ร 1000 = 15/10 ร 1000 = 1500 m We know that, Speed of sound = Wavelength ร Frequency v = ๐ ร f v = 0.35 ร 2000 v = 35/100 ร 2000 v = 700 m/s We know that, Speed = ๐ท๐๐ ๐ก๐๐๐๐/๐๐๐๐ Time = ๐ท๐๐ ๐ก๐๐๐๐/(๐๐๐๐๐ ๐๐ ๐ ๐๐ข๐๐) = 1500/700 = 15/7 = 2.1 s Time taken by sound is 2.1 s

Class 9

Chapter 12 Class 9 - Sound

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.