8-70. The pitch of a sound can be described as 

 being 



1. high, if it contains many overtones; 

 low, if it contains few overtones 



2. low, if the wave is transverse; high, 

 if the wave is longitudinal 



3. low, if the frequency is low; high, 

 if the frequency is high 



4. high, if the wavelength is long; low, 

 if the wavelength is short 



8-71. What unit is used to measure the 

 intensity of sound? 



1. Hertz 



2. Cycle 



3. Decibel 



4. Radian 



8-72. The sound of the siren of a slow-moving 

 police car is heard some distance away 

 by a listener. As the police car 

 approaches the listener the car increases 

 its speed. The pitch of the siren will 

 appear to the listener to 



1. become lower 



2. become higher 



3. remain the same 



4. become lower as the police car 

 approaches, but to become higher as 

 it passes and recedes 



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