Wave Motion 4 Question 33

31. A source of sound of frequency 256Hz is moving rapidly towards a wall with a velocity of 5m/s. How many beats per second will be heard by the observer on source itself if sound travels at a speed of 330m/s ?

(1981, 4M)

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Answer:

Correct Answer: 31. 7.87 Hz

Solution:

  1. Frequency heard by the observer due to S (reflected wave)

f=f(v+vovvs)=256(330+53305)=263.87Hz

Beat frequency fb=ff=7.87Hz



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