A) 2
B) 4
C) 8
D) 10
Correct Answer: D
Solution :
[d] Frequency of sound produced by siren, \[f=800Hz\] Speed of observer, u = 2 m/s Velocity of sound, v = 320 m/s No. of beats heard per second =? No. of extra waves received by the observer per second \[=\pm \,\,4\lambda \] \[\therefore \] No. of beats/ sec \[=\frac{2}{\lambda }-\left( -\frac{2}{\lambda } \right)=\frac{4}{\lambda }\] \[=\frac{2\times 2}{\frac{320}{800}}=\frac{2\times 2\times 800}{320}=10\] \[\left( \therefore \lambda =\frac{V}{f} \right)\]You need to login to perform this action.
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