and Sound Music, Physics 1240 Exam II, Thursday, March 16, 2006 Please print your name ___________________________________________ Fill out the exam solution form as instructed. If you do not put both your name and student ID number on the solution form you may loose 10 points. These solution forms will not be returned to you. You may keep this copy of the exam. Circle your answers on this copy of the exam for you own record . Each problem is worth 4 points. This exam has a total of 100 points. Choose the best answer. Good luck! 1. The measured intensity of sound waves from two sources is the following. Source A has an intensity of 1 W/m2 and source B has an intensity of 9 W/m2. The amplitude of the sound wave from source B is a. 3 times larger than that from source A b. 3 times smaller than that from source A c. 9 times larger than that from source A d. 9 times smaller than that from source A e. none of the above 2. A band's drummer is out of control! Her intensity is 0.1 W/m2, while the rest of the band has a combined intensity of 0.0001 W/m2. How many dB is the drummer's SIL relative to the rest of the band? a. 90 dB b. 100 dB c. 10 dB d. 20 dB e. 30 dB 3. Loudness is a psychological quantity or sensation that is determined by knowing the sound intensity level in dB. a. true, loudness and SIL are related in a way similar to the relationship between pitch and frequency b. false, multiple physical quantities determine loudness 4. What is the loudness of a 100 dB 1000 Hz tone? a. 100 phons b. 40 sones c. 100 dB d. 0.0001 W/m2 e. none of the above 5. The volume of an amplifier is decreased so that a loud sound decreases by a factor of 1,000 in intensity (measured in W/m2). How will the quality of the sound change? a. the pitch will go down 30 dB b. the pitch will go up 30 dB c. the bass frequency range will sound loud louder d. the bass frequencies will sound weaker e. the perceived quality of the sound will be change very little, if at all. It will just be 30 dB louder
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6. Suppose A=221 Hz. What would be the frequency of the C above it? a. 278.44 Hz b. 234.14 Hz c. 248.06 Hz d. 262.81 Hz e. impossible to determine 7. The volume on an audio amplifier increased so that the SIL is increased 40dB. How much of an increase is that in sound intensity (W/m2)? a. a factor of 40 b. a factor of 10,000 c. a factor of 400 d. a factor of 4 e. none of the above 8. The waveform is recorded for both a clarinet and a flute. The period of both waveforms is 0.002 s. The sound intensity level of both instruments was measured as well and both instruments played with an SIL of 60 dB. The two musical instruments sound different to a listener because a. pitch b. loudness c. timbre d. the two instruments sound the same 9. If you hear two pure tones with f=1,000 Hz and f=5,000 Hz, both at 60 dB SIL, which will be the loudest? a. 1,000 Hz b. 5,000 Hz c. they will have the same loudness 10. What is an important function of the auditory canal? a. converting sound waves to neural impulses b. protection of the eardrum c. vibration of the semi-circular canals d. vibration of the basilar membrane 11. When different parts of the basilar membrane are excited, what information does this provide? a. information relating to the frequency spectrum information b. relating to the sound intensity c. information very similar to a digital sample of the waveform 12. What two pure toness would sound more pleasing if played at the same time a. 440 Hz, 466.16 Hz b. 440 Hz, 660 Hz c. neither a. nor b. because consonance and dissonance are completely subjective 13. If we choose the frequency of A to be 442 Hz (as in the case in some European countries), a. we can no longer preserve the constancy of the ratio of adjacent half steps b. we can no longer define the octave as a factor of two interval c. we can still form an equally tempered scale d. none of the above
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14. What is the frequency of a perfect fifth above 200 Hz? a. 150 Hz. b. 250 Hz c. 300 Hz d. 400 Hz 15. Why is the major 3rd interval a factor of 1.26 in equal-tempered tuning rather than 1.25=5/4? a. Pythagoras preferred the 1.26 ratio b. An error was made in the 1930's, and this has been convention ever since c. A compromise is made to produce a constant frequency ratio for all half step intervals 16. What sound intensity level (dB) is required for a 40 phon loudness at 80 Hz? a. 25 dB b. 43 dB c. 54 dB d. 65 dB 17. Choose the answer that best describes a function of the ossicles? a. perform frequency analysis of sound waves b. the anvil acts as a resonator c. the stirrup vibrates the oval window d. the hammer bone keeps the cochlea properly positioned e. the hammer bone keeps the basilar membrane taught 18. What type of synthesis technique would best reproduce the sound of French horn? a. additive synthesis b. subtractive synthesis c. digital sample synthesis d. FM synthesis e. none of the above 19. Suppose a synthesizer played a French horn sound. First, a quarter note is played lasting 0.5 seconds. Second, a whole note lasting 2 seconds is played at the same pitch. What changes? a. attack b. decay c. sustain d. release e. FM modulation rate 20. Under the cover of night, a Girl Scout signals her friends on a ...