The driver of a car travelling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is:

Question

Dr. Abubacker · Accepted Answer

[Solution from source] The hill receives f₁ = 600 × 330/(330 − 30) from the approaching car and reflects it; the driver, moving towards the hill, hears f = f₁ × (330 + 30)/330 = 600 × 360/300 = 720 Hz. The reflected sound is heard at a higher, not lower, frequency. Answer (2).

Q. The driver of a car travelling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is:

Explanation

Reviewed by Dr. Abubacker

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