WBJEE · Physics · Waves and Sound
\(A\) train is moving with a uniform speed \(c^{2}\) \(33 \mathrm{m} / \mathrm{s}\) and an observer is approaching the train with the same speed. If the train blows a whistle of frequency \(1000 \mathrm{Hz}\) and the velocity of sound is \(333 \mathrm{m} / \mathrm{s},\) then the apparent frequency of the sound that the observer hears is
- A \(1220 \mathrm{Hz}\)
- B \(1099 \mathrm{Hz}\)
- C \(1110 \mathrm{Hz}\)
- D \(1200 \mathrm{Hi}\)
Answer & Solution
Correct Answer
(A) \(1220 \mathrm{Hz}\)
Step-by-step Solution
Detailed explanation
We have, Apparent frequency, \(\mathrm{v} =\left(\frac{v+u_{0}}{v-u_{s}}\right)\mathrm{v}_{0}=\left(\frac{333+33}{333-33}\right) \times 1000 \\=\frac{366}{300} \times 1000=1220 \mathrm{Hz}\)
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