HANDBOOK OF ACOUSTICS - online book

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

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EXAMINATION PAPERS.
271
(b) The temperature of the air through which a series of sound­waves is passing is very slightly raised in temperature, in consequence of the kinetic energy of the moving air particles being slowly trans­formed into the kinetic energy of heat, just as the energy of a train in motion is changed into heat when the brakes are applied and it is brought to rest.
5.    Two organ pipes, one open and the other closed, are sounding the same fundamental note.
(a)  What is the ratio of the lengths of the pipes P (5) Are the notes exactly alike ?
(<?) And if not, account for their difference.
Am. (a) Length of the open pipe : length of the closed pipe as 2 : 1.
(J) No.
{e) The notes are both more or less compound, that from the open pipe will consist of the fundamental, its octave, octave fifth, and so on; while that from the closed pipe will consist of the partials of the odd series only, viz., the fundamental, octave fifth, &c.
6.  (a) What is meant by resonance, and how are resonant effects explained ?
(b)  A column of air resounding to a note 256 complete vibrations per second is obtained by filling a tall narrow jar with water, and then allowing the water to escape gradually through a stop-cock at the bottom, till maximum resonance is obtained. Find at least two other notes to which the same column of air would resound.
Am. (a) See pp. 67 and 58.
(*) 256 x 3 = 768 and 256 X 5 = 1280.
ROYAL UNIVERSITY OF IRELAND.
Honour Examination in Music, 1895.
1.    Give an expression for the velocity of propagation of transverse vibrations along a stretched string. Deduce Bernoulli's Laws for the vibrations of stretched strings.
Am.—See p. 87.
2.    Explain how it is that in a column of air in stationary vibration, the length of a ventral segment is a half-wave length.
Am— See pp. 102, 105, 106.
3.  (a) What is meant by a gamut of equal temperament ?
(b) Find the arithmetical value of the interval of a tone on this gamut. Am. {a) See p. 238.
(b) Nearly L^2i = t» 1           400