OK, let's see the correct answers.
OK, let's see the correct answers.
CD202, R. Lutfi Exam I. Physical Acoustics 10/19/94 1.) The branch of physics that deals with pure motion: a. Kinematics b. Dynamics c. Statistics d. Astrology 2.) Which of the following is a unit of pressure? a. dyne b. erg c. watts d. dyne/cm2 3.) The rate at which energy is expended is the definition of: a. force b. work c. power d. pressure 4.) Which of the following is a derived measure a. mass b. time c. length d. force 5.). In the expression Asin(wt ) a. sin is a function and wt is the argument to this function b. sin(wt) is the vertical projection of uniform circular motion c. A is amplitude and w is angular velocity d. all of the above 6.) How many log units are there in the number 0.001? a. 3 b. -3 c. 0.01 d. 100 7). Which of the following is the definition of dB SPL a. 20 times the log of a pressure value expressed relative to 0.0002 dynes/cm2 b. 20 times the log of a power ratio c. 10 times the log of a pressure ratio d. The lowest intensity of sound that one can hear 8.) 51 dB re: 0.1 watt is how many dB re: 0.2 watts? a. 48 dB re: 0.2 watts b. 54 dB re: 0.2 watts c. 57 dB re: 0.2 watts d. 61 dB re: 0.2 watts 9.) Which of the following is true of the spring-mass equation for motion: a. it satisfies the property of superposition b. it requires that the acceleration of them mass be opposite in sign to its displacement c. sums of sinusoids satisfy the equation d. all of the above are true 10.) Standing waves typically occur a. in the free field where there are no obstacles b. in enclosed sound fields where there is little energy loss c. whenever sound travels from one medium to another d. none of the above 11.) Any sinusoid is completely specified by its a. frequency, amplitude, and power spectrum b. amplitude, rms, and phase c. frequency, amplitude, and starting phase d. frequency, amplitude, and period 12.) What is the rms of the following instantaneous amplitude values: 4, 0,-2,1,2? a. 25 b. 5 c. square root of 5 d. none of the above 13.) What information is there in the amplitude spectrum of a time waveform? a. the phase of the individual frequencies comprising the waveform b. the amplitudes of the individual frequencies comprising the waveform c. the transfer function of the filter d. all of the above 14.) The power spectrum of a gated 500-Hz sinusoid is a. sinx/x b. a single vertical line at 500-Hz c. a collection of vertical lines spaced 500-Hz apart d. flat 15.) The spring-mass system is in resonance when the inertial force of the mass is a. greater than the restoring force of the spring b. negligible c. equal in magnitude and sign to the driving force d. equal in magnitude but opposite in sign to the elastic force of the spring 16.) The output of a linear system with sinusoidal driving force is a. the transfer function b. unpredictable c. an amplitude-scaled and phase-shifted version of the input sinusoid d. none of the above 17.) Two DIFFERENT time waveforms with identical amplitude spectra must have a. different phase spectra b. different frequencies c. different transfer functions d. none of the above 18.) A nonlinear system is one that a. contains frequencies in the output that are not present in the input b. obeys the principle of superposition c. has no resonant frequency d. none of the above
