JEE Mains · Physics · STD 11 - 14. waves and sound
A person observes two moving trains, '\(A\)' reaching the station and '\(B\)' leaving the station with equal speed of \(30\,m / s\). If both trains emit sounds with frequency \(300\,Hz\), (Speed of sound : \(330\,m / s\) ) approximate difference of frequencies heard by the person will be \(..........Hz\)
- A \(33\)
- B \(55\)
- C \(80\)
- D \(10\)
Answer & Solution
Correct Answer
(B) \(55\)
Step-by-step Solution
Detailed explanation
\(f _1=300\left(\frac{330-0}{330-(-30)}\right)=275\) \(f _2=300\left(\frac{330-0}{330-(30)}\right)=330\) \(\Delta f =330-275=55\,Hz\)
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