Home
Class 11
PHYSICS
A whistle revolves in a circle with an a...

A whistle revolves in a circle with an angular speed of `20 rad//sec` using a string of length `50 cm`. If the frequency of sound from the whistle is `385 Hz`, then what is the minimum frequency heard by an observer which is far away from the centre in the same plane? `v=340m//s`

A

333 Hz

B

374 Hz

C

385 Hz

D

394 Hz

Text Solution

Verified by Experts

The correct Answer is:
B
Speed `v=romega=0.5xx20=10m//s`
`f_(min)=f((v)/(v+v_(s)))=385((340)/(340+10))=374Hz`
Promotional Banner

Topper's Solved these Questions

  • WAVES AND SOUND

    ERRORLESS|Exercise NCERT BASED QUESTIONS (MUSICAL SOUND) |17 Videos

  • WAVES AND SOUND

    ERRORLESS|Exercise PAST YEARS QUESTIONS |45 Videos

  • WAVES AND SOUND

    ERRORLESS|Exercise NCERT BASED QUESTIONS (ORGAN PIPE (VIBRATION OF AIR COLUMN)) |16 Videos

  • UNITS, DIMENSIONS AND MEASUREMENT

    ERRORLESS|Exercise ASSERTION & REASON |17 Videos

  • WORK, ENERGY POWER AND COLLISION

    ERRORLESS|Exercise ASSERTION & REASON |22 Videos

Similar Questions

Explore conceptually related problems

(i) What is beat phenomenon? (ii) A whistle revolves in a circle with angular velocity of omega=20rads^(-1) . If the frequency of sound is 385 Hz and speed is 340 ms^(-1) , then find the frequency heard by the observer when the whistle is at B.

A disc of radius R is rotating uniformly with angular frequency . A source of sound is fixed to the rim of the disc. The ratio of maximum to minimum frequency heard by a stationary observer, far away from the disc and in the plane of the disc is: (v = speed of sound)

A whistle emitting a loud sound of frequency 540 Hz is whirled in a horizontal circle of radius 2 m and at a constant angular speed of 15 rad//s . The speed of sound is 330 m//s . The ratio of the highest to the lowest frequency heard by a listener standing at rest at a large distance from the center of the circle is

An observer and a source both are moving away with velocity 20 m/s each in opposite direction. If frequency of sound observed is 1800Hz then what is actual frequency (velocity of sound= 340 m/s)

A train approaching a railway platform with a speed of 20 m s^(-1) starts blowing the whistle. Speed of sound in air is 340 m s^(-1) . If the frequency of the emitted sound from the whistle is 640 Hz, the frequency of sound as heard by person standing on the platform

A car is moving along X-axis with a velocity v=20m//s . It sounds a whistle of frequency 660 Hz. If the speed of sound is 340m//s . The apparent frequency heard by the observer O (shown in figure) is:

ERRORLESS-WAVES AND SOUND -NCERT BASED QUESTIONS (DOPPLER.S EFFECT)
  1. A source of sound is travelling towards a stationary observer. The fre...

    Text Solution

    |

  2. Suppose that the speed of sound in air at a given temperature is 400...

    Text Solution

    |

  3. A whistle revolves in a circle with an angular speed of 20 rad//sec us...

    Text Solution

    |

  4. A siren emitting sound of frequency 800Hz is going away from a static ...

    Text Solution

    |

  5. A source and an observer approach each other with same velocity 50 m/s...

    Text Solution

    |

  6. A speed ign motorcyclist sees traffic ham ahead of him. He slows doen ...

    Text Solution

    |

  7. A train is moving with a uniform speed of 33 m/s and an observer is ap...

    Text Solution

    |

  8. A source producing sound of frequency 170 Hz is approaching a stationa...

    Text Solution

    |

  9. A train approaches stationary observer, the velocity of train being 1/...

    Text Solution

    |

  10. A whistle of frequency 500 Hz tied to the end of a string of length 1....

    Text Solution

    |

  11. A car sounding a horn of frequency 1000 Hz passes an observer. The rat...

    Text Solution

    |

  12. A small source of sound moves on a circle as shown in figure and an ob...

    Text Solution

    |

  13. A man is watching two trains, one leaving and the other coming in with...

    Text Solution

    |

  14. A train whistling at constant frequency is moving towards a station at...

    Text Solution

    |

  15. A car is moving with 90 km h^(-1) blows a horn of 150 Hz, towards a cl...

    Text Solution

    |

  16. A source and an observer move away from each other with a velocity of ...

    Text Solution

    |

  17. A source is moving towards an observer with a speed of 20 m / s and ha...

    Text Solution

    |

  18. A police car moving at 22 m/s, chases a motorcylist. The police man so...

    Text Solution

    |

  19. A whistle emitting a loud sound of frequency 540 Hz is whirled in a ho...

    Text Solution

    |

  20. A source of sound of frequency 500 Hz is moving towards an observer wi...

    Text Solution

    |