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MHT CET202020 Oct 2020Morning ShiftPhysicsWaves and SoundActual

A source of sound is moving with constant velocity of 30 ~m / s emitting a note of frequency 256 ~Hz . The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him is [speed of sound in air =330 ~m / s ]

Options

  1. A8: 9
  2. B9: 8
  3. C5: 6
  4. D6: 5

Correct answer

D. 6: 5

Step-by-step solution

A source of sound is moving with constant velocity of 30 mis emitting a note of frequency 256 ~Hz . The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him is 6: 5 . V_ S =30 ~m / s n ₀=256 ~Hz n₁=n₀ V V-V_ s n₂=n₀ V V+V_ s n₁ n₂ = V+V_ s V-V_ s = 360 300 = 6 5

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