HANDBOOK OF ACOUSTICS - online book

A complete view of Acoustical Science & its bearings on music, for musicians & music students.

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274                 HAXD-BOOK OF ACOUSTICS.
The Smaller Diesis is difference between five major thirds and a twelfth.
---- J A I A 4 .* f A. 4 ^ 3         3 07S
4.    If a copper wire, density 9, 75 cm. in length, and '6 m.m. in thickness, gives 200 vibrations per second when stretched by a weight of 10 kilogrammes, how many vibrations per second will a steel wire, density 7*5, one metre in length, and 1 m.m. in thickness, give when stretched by 27 kilogrammes ?
Arts.—By the laws given on pp. 87 or 96 number of vibrations per sec.
= 200 X y/9        75 -6 \/27
yrE x 100 x T x yio ~
200 X 3 X 6 X 3 X-y/27        5X3X6X3X -y/27
4 X 10 X y/Ys X -v/lO                                     ^As
V^9         270 X 3           .„
270 X 2L__ =              _ = 162
/25                    5
5.  (a) Find all the overtones that are possible in an organ pipe closed at one end. {b) Draw a figure to show the directions in which the air particles are moving at a given instant when the pipe is emitting its first overtone.
Am. (a) See pp. 106 and 107.
(*)
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6.    Give a brief account of what causes difference in timbre or quality in sounds.
Ans.—See pp. 74 and 75.
7.   (a) Describe how reeds vibrate.
(b) Explain why the tones they give are generally harsh. Ans. (a) See p. 110. [b) See p. 111.
8.  (a) Explain what is meant by the interference of two sounds. (b) Describe experiments illustrating it.
Am. (a) See pp. 136, 137. (*) See p. 139 or 140 or 141.
9.    Draw diagrams to show the result of compounding a note with its octave in two different phases.
Am.—See p. 83.