TS EAMCET · Physics · Waves and Sound
A drone fitted with siren in flying directly away from the drone operator and towards a distant building at a speed of \(15 \mathrm{~m} / \mathrm{s}\). The siren produces sound of frequency \(780 \mathrm{~Hz}\). What is the frequency that the operator hears in the echo reflected from the building. [Speed of sound is \(340 \mathrm{~m} / \mathrm{s}\).]
- A \(766 \mathrm{~Hz}\)
- B \(800 \mathrm{~Hz}\)
- C \(816 \mathrm{~Hz}\)
- D \(840 \mathrm{~Hz}\)
Answer & Solution
Correct Answer
(C) \(816 \mathrm{~Hz}\)
Step-by-step Solution
Detailed explanation
\[ \text { A drone fitted with siren as shown in the figure, } \] Given, speed of drones, \(v_s=15 \mathrm{~m} / \mathrm{s}\), actual frequency, \(n_0=780 \mathrm{~Hz}\) and speed of sound, \(v=340 \mathrm{~m} / \mathrm{s}\) As source is moving towards the building, so the…
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