2. Questions Bank
  3. JEE Main & Advanced
  4. Physics
  5. Wave Mechanics

JEE Main & Advanced Physics Wave Mechanics Question Bank Doppler's Effect

  • question_answer
    A person feels 2.5% difference of frequency of a motor-car horn. If the motor-car is moving to the person and the velocity of sound is 320 m/sec, then the velocity of car will be                     [CPMT 1981; MP PET 1989]

    A)            8 m/s (approx.)                   

    B)            800 m/s

    C)            7 m/s                                       

    D)            6 m/s (approx.)

    Correct Answer: A

    Solution :

               By Doppler?s formula \[n'=\frac{nv}{(v-{{v}_{S}})}\]                    Since, source is moving towards the listener so \[n'>n\].                    If n = 100 then n' = 102.5                    Þ \[102.5=\frac{100\times 320}{(320-{{v}_{S}})}\] Þ \[{{v}_{s}}=8\]\[m/\sec \]


You need to login to perform this action.
You will be redirected in 3 sec spinner