Gangs of PCM
JEE Mains 7th January, 2020 Evening Shift.
This question is from chapter “Waves” or “Mechanical Waves”.
To solve this question we need to know the concepts “Doppler Effect”, ”Beats”, and “Relative Velocity”.
Question:
A stationary observer receives sound from two identical tuning forks, one of which approaches and the other one recedes with the same speed (much less than the speed of sound). The observer hears 2 beats/sec. The oscillation frequency of each tuning fork is ν_o = 1400 Hz and the velocity of sound in air is 350 m/s. The speed of each tuning fork is close to :
a) 1/4 m/s b) 1/2 m/s c) 1 m/s d) 1/8 m/s
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