JEE Mains · Physics · STD 11 - 14. waves and sound
Two cars \(A\) and \(B\) are moving away from each other in opposite directions. Both the cars are moving with a speed of \(20\, ms^{-1}\) with respect to the ground. If an observer in car \(A\) detects a frequency \(2000\, Hz\) of the sound coming from car \(B\), what is the natural frequency of the sound source of car \(B\) .... \(Hz\) ? (speed of sound in air \(= 340\, ms^{-1}\))
- A \(2250\)
- B \(2060\)
- C \(2150\)
- D \(2300\)
Answer & Solution
Correct Answer
(A) \(2250\)
Step-by-step Solution
Detailed explanation
Doppler effect: \(f=\left(\frac{v+u_{0}}{v-u_{s}}\right)\left(f_{0}\right)\) \(2000=\left(\frac{340+(-20)}{340-(-20)}\right)\left(f_{0}\right)\) \(\mathrm{f}_{\mathrm{o}}=2250 \mathrm{Hz}\)
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