AP EAMCET · PHYSICS · Waves and Sound
A vehicle sounding a whistle of frequency \(256 \mathrm{~Hz}\) is moving on a straight road, towards a hill with a velocity of \(10 \mathrm{~ms}^{-1}\). The number of beats per second observed by a person travelling in the vehicle is velocity of sound \(=330 \mathrm{~ms}^{-1}\)
- A zero
- B 10
- C 14
- D 16
Answer & Solution
Correct Answer
(D) 16
Step-by-step Solution
Detailed explanation
Apparent frequency heard by the observer, \(\begin{aligned} n^{\prime} & =\left(\frac{v+v_s}{v-v_s}\right) \times n \\ & =\left(\frac{330+10}{330-10}\right) \times 256 \\ & =\frac{340}{320} \times 256=272 \mathrm{~Hz} \end{aligned}\) \(\therefore\) Number of beats heard by the…
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