A man is watching two trains, one leaving and the other coming in with – McqOptions

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1.	A man is watching two trains, one leaving and the other coming in with equal speeds of 4 m/sec. If they sound their whistles, each of frequency 240 Hz, the number of beats heard by the man (velocity of sound in air = 320 m/sec) will be equal to [NCERT 1984; CPMT 1997; MP PET 1999; RPMT 2000; BHU 2004, 05]
A.	6
B.	3
C.	0
D.	12
Answer» B. 3

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