A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz. The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be [MP PET 1994]

9 : 10 (Speed of sound v = 340 m/s)

A source of sound is moving with constant velocity of 20 m/s emitting

1.	A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz. The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be [MP PET 1994]
A.	9 : 8
B.	8 : 9
C.	7.6 mm
D.	9 : 10 (Speed of sound v = 340 m/s)
Answer» B. 8 : 9

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A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz. The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be [MP PET 1994]

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