SATHEE: Wave Motion 4 Question 27

Wave Motion 4 Question 27

25. A band playing music at a frequency $f$ is moving towards a wall at a speed $v_{b}$ . A motorist is following the band with a speed $v_{m}$ . If $v$ is the speed of sound. Obtain an expression for the beat frequency heard by the motorist.

(1997, 5M)

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Answer:

Correct Answer: 25. (d)

Solution:

Frequency received in case 1 .

$f_{1} = f (\frac{v + v_{m}}{v + v_{b}})$

and in case 2, $f_{2} = f (\frac{v + v_{m}}{v - v_{b}})$

Obviously, $f_{2} > f_{1}$

$∴$ Beat frequency,

$\begin{aligned} f_{b} = f_{2} - f_{1} & = f (\frac{v + v_{m}}{v - v_{b}}) - f (\frac{v + v_{m}}{v + v_{b}}) \\ or f_{b} & = \frac{2 v_{b} (v + v_{m})}{v^{2} - v_{b}^{2}} \end{aligned}$

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Wave Motion 4 Question 27

25. A band playing music at a frequency $f$ is moving towards a wall at a speed $v_{b}$ . A motorist is following the band with a speed $v_{m}$ . If $v$ is the speed of sound. Obtain an expression for the beat frequency heard by the motorist.

Answer:

इंजीनियरिंग की तैयारी

चिकित्सा तैयारी

एनसीईआरटी पुस्तकें और समाधान

महत्वपूर्ण संसाधन

अन्य संसाधन

पाठ्यक्रम

परीक्षा मंच

नमूना मॉक टेस्ट

सदस्यता

एनसीईआरटी व्यायाम वीडियो समाधान

Wave Motion 4 Question 27

25. A band playing music at a frequency f is moving towards a wall at a speed vb. A motorist is following the band with a speed vm. If v is the speed of sound. Obtain an expression for the beat frequency heard by the motorist.

Answer:

इंजीनियरिंग की तैयारी

चिकित्सा तैयारी

एनसीईआरटी पुस्तकें और समाधान

महत्वपूर्ण संसाधन

अन्य संसाधन

पाठ्यक्रम

परीक्षा मंच

नमूना मॉक टेस्ट

सदस्यता

एनसीईआरटी व्यायाम वीडियो समाधान

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25. A band playing music at a frequency $f$ is moving towards a wall at a speed $v_{b}$ . A motorist is following the band with a speed $v_{m}$ . If $v$ is the speed of sound. Obtain an expression for the beat frequency heard by the motorist.