HAND-BOOK OF ACOUSTICS.
71. What is meant by the intensity of a musical sound ? How can it be shown experimentally, that the intensity of a sound depends upon the amplitude of the vibrations that give rise to it ?
72. State the law of Inverse squares. Why does it not appear to be correct, under ordinary circumstances ?
73. What is the principle of the speaking tube ?
74. Explain the phenomenon of echoes.
75. If two seconds elapse between a sound and ita echo, what is the distance of the reflecting surface ?
76. Explain one of the causes of the bad acoustical properties of some buildings, and state any remedy you know of.
77. Why does one's voice appear louder in an empty unfurnished room, than in the same room furnished ?
78. Give a theoretical proof of the law of Inverse Squares.
79. How can the phenomenon of resonance or co-vibration be illustrated with two tuning-forks? What conditions are necessary to the success of the experiment ?
80. Describe some experiments with stretched strings to illustrate the phenomenon of resonance.
81. Explain in detail the cause of resonance or co-vibration in the case of tuning-forks or stretched strings.
82. Explain in detail the cause of resonance in open tubes, showing clearly why the tube must be of a certain definite length, if it is to resound to a note of given pitch.
83. Explain in detail the cause of resonance in stopped tubes, showing clearly why the tube must be of a certain definite length, if it is to resound to a note of given pitch.
84. How would you construct a resonator to resound to G1 ? Calculate approximate dimensions.
85. To illustrate the phenomenon of resonance with two tuning-forks, they must be in the most perfect unison; whereas an approximate unison is sufficient in the case of two strings stretched on the same sound-board. Explain this.
86. I have a tube 1 inch in diameter, open at both ends, which resounds powerfully to GJ. What length is it ? (C = 512).
87. Calculate the length of a stopped tube about 1 inch in diameter, resounding to EJ7.
88. A tube open at both ends, and about an inch in diameter, is lOj inches long. Calculate approximately the note it resounds to.