JEE Mains · Physics · STD 11 - 14. waves and sound
A stationary source emits sound waves of frequency \(500\, Hz\). Two observers moving along a line passing through the source detect sound to be of frequencies \(480\, Hz\) and \(530\, Hz\). Their respective speeds are, in \(m\,s^{-1}\) (Given speed of sound \(= 300\, m/s\))
- A \(16, 14\)
- B \(12, 16\)
- C \(8, 18\)
- D \(12, 18\)
Answer & Solution
Correct Answer
(D) \(12, 18\)
Step-by-step Solution
Detailed explanation
\( v= \frac{v+v_{0}}{v} v_{0}\) \(\Rightarrow v_{0}=\left(\frac{v}{v_{0}}-1\right) v\) \(v_{0}=\left(\frac{530}{500}-1\right) 300=18 \mathrm{m} / \mathrm{s}\) \(v_{0}=\left|\left(\frac{480}{500}-1\right) 300\right|=12 \mathrm{m} / \mathrm{s}\)
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