When a source of sound is in motion towards a stationary observer, then a change in wave
Correct answer: C. Increase in frequency of sound
- A. Increase in the velocity of sound
- B. Decrease in the velocity of sound
- C. Increase in frequency of sound
- D. Increase in both velocity and frequency of sound
Explanation
As per the dopplers equation When source is moving towards observor the velocity of source is substracted from the velocity of sound. The value of the denominator in the equation is lower (as compared to when source is moving away and the velocities add up) causing an increase the observed frequancy. Fo = Fs {(V- Vo) / (V - Vs)} Where, Fo = Observed frequency Fs = Frequency generated by the source V = Speed of sound Vs = Speed of source Vo = Speed of observor (who in this case is stationary and so it will be zero)
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Progressive waves transfer energy through oscillations, with wavelength, frequency, amplitude and wave speed related by v = fλ; sound speed depends on the medium. Superposition produces interference and stationary waves in strings and organ pipes, while simple harmonic motion describes the oscillation itself and must be distinguished from wave propagation.
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