A) 2486 Hz
B) 2070 Hz
C) 2134 Hz
D) 1872 Hz
Correct Answer: B
Solution :
Key Idea: Movement of the source and observer alters the wavelength and the perceived frequency of sound. As both source and observer are moving away, so observed frequency decreases. \[\therefore \] \[f=\left( \frac{v-{{v}_{0}}}{v+{{v}_{s}}} \right)f\] where\[v\]is the velocity of sound\[~=340\text{ }m/s\] Here,\[{{v}_{0}}=20\,m/s,\,{{v}_{s}}=20\,m/s,f=1840\,Hz\] \[\therefore \] \[1840=\left( \frac{340-20}{340+30} \right)f\] or \[f=\frac{1840\times 360}{320}=2070\,Hz\]You need to login to perform this action.
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