MHT CET · Physics · Waves and Sound
A person observes two moving trains. First reaching the station and another leaves the station with equal speed of \(30 \mathrm{~m} / \mathrm{s}\). If both trains emit sounds of frequency 300 Hz , difference of frequencies heard by the person will be (speed of sound in air \(=330 \mathrm{~m} / \mathrm{s}\) )
- A 80 Hz
- B 75 Hz
- C 55 Hz
- D 45 Hz
Answer & Solution
Correct Answer
(C) 55 Hz
Step-by-step Solution
Detailed explanation
\(f_{appr} = f_s \left( \frac{v}{v - v_s} \right)\) \(f_{appr} = 300 \left( \frac{330}{330 - 30} \right) = 330 \, \text{Hz}\)
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