How does the sound produced by a vibrating object in a medium reach your ear? (Page 162 )
When an object vibrates, it vibrates the neighbouring particles of the medium. These vibrating particles then vibrate to the adjacent particles In this way, vibrations produced by an object are transferred from one particle to another till it reaches to our ear. Page 163 Explain how sound is produced by your school bell. Ans: When the bell moves backwards, it creates a region of low pressure know as rarefaction. As the bell continues to move forward and backward, it creates a series of compressions and rarefactions. This produce the sound of a bell Why sound waves are called mechanical waves? Ans: Sound waves need the material medium to vibrate and propagate. Hence, these waves are known as mechanical waves. Sound waves propagate through a medium because of the interaction of the particles present in that medium. Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend? Sound needs a medium to propagate. Since there is no material medium on the moon due to absence of atmosphere, you cannot hear any sound on the moon. Page 166 Which wave property determines (a) loudness, (b) pitch? (a) Amplitude of sound wave determines the loudness of a sound. The amplitude of a sound directly proportional to amplitude of wave. If the amplitude of a sound is large, then the sound produced will also be loud. (b) Frequency of sound wave determines the pitch of a sound. The pitch of a sound is proportional to its frequency. High pitched sounds have high frequency Guess which sound has a higher pitch: guitar or car horn? The frequency of the vibration of a sound produced by a guitar is greater than that produced by a car horn. As we know that the pitch of a sound is directly proportional to its frequency, the guitar has a higher pitch than a car horn. Read full solution and test paper 9th_science_ncert_solution_chap.-sound Download File IX-Physics for term-II Sound CBSE Test paper Download File More use full link for physics study Physics class 9th Numerical for chapter sound CBSE TEST PAPER (Class-9)Work and Energy Numerical on work and energy for class 9 9th Question Bank chapter -Sound 9th Physics for term-II Sound NCERT Solutions
2 Comments
RiTz3
12/2/2012 04:14:50 am
thnz fo d hlp ................... warna to on mnday sachin sir wud hv killed .... thnku uh !!!
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TEENA SINGH
31/1/2014 08:23:14 am
Thank u very much
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