WBJEE · Physics · Waves and Sound
A car moving at a velocity of \(17 \mathrm{ms}^{-1}\) towards an approaching bus that blows a horn at a frequency of \(640 \mathrm{Hz}\) on a straight track. The frequency of this horn appears to be \(680 \mathrm{Hz}\) to the car driver. If the velocity of sound in air is \(340 \mathrm{ms}^{-1}\), then the velocity of the approaching bus is
- A \(2 \mathrm{ms}^{-1}\)
- B \(4 \mathrm{ms}^{-1}\)
- C \(8 \mathrm{ms}^{-1}\)
- D \(10 \mathrm{ms}^{-1}\)
Answer & Solution
Correct Answer
(B) \(4 \mathrm{ms}^{-1}\)
Step-by-step Solution
Detailed explanation
Given, velocity of sound, \(v=340 \mathrm{m} / \mathrm{s}\) Velocity of listner, \(v_{L}=17 \mathrm{m} / \mathrm{s}\) Velocity of source \(=v_{s}\) Frequency of hom emitted \[ v=640 \mathrm{Hz} \] The apparent frequency…
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