Oscillations and WavesDoppler Effect in Sound (NEET Physics): Questions 6  10 of 15
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Question number: 6
» Oscillations and Waves » Doppler Effect in Sound
Question
A whistle sends out 210 waves in a second. If the whistle approaches the observer with velocity 1/4 of the velocity of sound in air, the number of waves per second the observer will receive
Choices
Choice (4)  Response  

a.  384  
b.  320  
c.  182  
d.  280 
Question number: 7
» Oscillations and Waves » Doppler Effect in Sound
Question
A source of sound of frequency n is moving towards a stationary observer with a speed S. If the speed of sound in air is V and the frequency heard by the observer is n _{1}, the value of is,
Choices
Choice (4)  Response  

a. 
 
b. 
 
c. 
 
d. 

Question number: 8
» Oscillations and Waves » Doppler Effect in Sound
Question
A source of sound emitting a note of frequency 200 Hz moves towards an observer with a velocity v equal to the velocity of sound. If the observer also moves away from the source with the same velocity v, the apparent frequency heard by the observer is,
Choices
Choice (4)  Response  

a.  200 Hz  
b.  100 Hz  
c.  150 Hz  
d.  50 Hz 
Question number: 9
» Oscillations and Waves » Doppler Effect in Sound
Question
A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observes any beats
Choices
Choice (4)  Response  

a.  33 m/s  
b.  Zero  
c.  11 m/s  
d.  22 m/s 
Question number: 10
» Oscillations and Waves » Doppler Effect in Sound
Question
The speed of sound in air at a given temperature is 250 m/s. An engine blows whistle at a frequency of 810 cps. It is approaching the observer with velocity 25 m/s. The apparent frequency in cps heard by the observer will be
Choices
Choice (4)  Response  

a.  1100  
b.  800  
c.  900  
d.  1000 