Home
Class 11
PHYSICS
A siren placed at a railway platfrom is ...

A siren placed at a railway platfrom is emitted sound of frequency `5 kH_(Z)`, A passenger sitting in retun journey in a different train `B` he records a frequency of `6.0 kH_(Z)` while approaching the same siren. The ratio of the velocity of train `B` to that of train `A` is

A

`(242)/(252)`

B

`2`

C

`(5)/(6)`

D

`(11)/(6)`

Text Solution

Verified by Experts

The correct Answer is:
B
Using the formula
`f' = f((v + v_(0))/(v))`
we get `5.5 = 5 ((v + v_(A))/(v))`…….(1)
and `6.0 = 5((v + v_(B))/(v))`…..(2)
here `v =` speed of sound
`v_(A) =` speed of train `A`
and `v_(B) =` speed of train `B`
solving eqn. `(1)` and `(2)` we get :
`(v_(B))/(v_(A)) = 2`
Promotional Banner

Topper's Solved these Questions

  • SOUND WAVES

    RESONANCE ENGLISH|Exercise Exercise- 2 PART - II|20 Videos

  • SOUND WAVES

    RESONANCE ENGLISH|Exercise Exercise- 2 PART - III|19 Videos

  • SOUND WAVES

    RESONANCE ENGLISH|Exercise Exercise- 1 PART - II|30 Videos

  • SIMPLE HARMONIC MOTION

    RESONANCE ENGLISH|Exercise Exercise|28 Videos

  • STRING WAVES

    RESONANCE ENGLISH|Exercise Exercise|32 Videos

Similar Questions

Explore conceptually related problems

A siren placed at a railway platform is emitting sound of frequency 5 kHz . A passenger sitting in a moving train A records a frequency of 5.5kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. the ratio the velocity of train B to that of train A is

An observer standing on a railway crossing receives frequencies 2.2 kHz and 1.8 kHz when the tran approaches and recedes from the observer. Find the velocity of the train (speed of sound in air is 300 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 siren emitting a sound of frequency 1000 H_(Z) moves away from you towards a cliff at a speed of 10 m//s . (a) What is the frequency of the sound you hear coming directly from the sirven ? (b) What is the frequency of sounds you hear reflected off the cliffb ? (c) What beat frequency would you hear ? Take the speed of sound in air as 330 m//s .

A train, standing at the outer signal of a railway station blows a whistle of frequency 400Hz in still air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10ms^(-1) , (b) receeds from the platform with a speed of 10ms^(-1) ? (ii) What is the speed of sound in each case ? The speed of sound in still air can be taken as 340ms^(-1)

A train standing at the outer signal of a railway station, blows a whistle of frequency 400 Hz in stil air. (i) What is the frequency of the whistle for a platform observer when the train (a) approaches the platform with a speed of 10 ms^(-1) . (b) recedes from the platform with a speed of 10 ms ? What is the speed of sound in each case? (V=340ms^(-1)) .

The vector difference between the absolute velocities of two bodies is called their relative velocity. The concept of relative velocity enables us to treat one body as being at rest while the other is in motion with the relative velocity. This jormalism greatly simplifies many problems. If vecv_(A) is the absolute velocity of a body A and vec_(B) that of another body B then the relative velocity of A in relation to B is vec_(AD)=vecV_(A)-vecv_(B) and vecv_(BA)=vecv_(B) - vecv_(A) . The principle follows here is that the relative velocity of two bodies remains unchaged if the same additional velocity is imparted to both the bodies. A simple way of carrying out this operation is to be represent the velocities in magnitude and direction from a common point. Then the line joining the tips of the vectors represents the relative velocity Q A train A moves to the east with velocity of 40 km/hr and a train B moves due north with velocity of 30 km/hr. The relative velocity of A w.rt. B is

Statement I: A person is standing near a railway trach. A train is moving on the track. As the train is approaching the person, apparent freqeuncy keeps on increasing and when the train has passed the person, then apparent freqeuncy keeps on decreasing. Statement II: When train is approaching the person then, f=f_0[(c )/(c-u)] and when train is moving away from person f=f_0[(c )/(c+u)] Here, c is velocity of sound u is velocity of train and f_0 is original frequency of whistle.

A railroad train is travelling at 30.0 m//s in still air. The frequency of the note emitted by the train whistle is 262 H_(Z) . What frequency is heard by a passenger on a train moving in the opposite direction to the first at 18.0 m//s and (a) approaching the first? (b) receding from the first? Speed of sound in air = 340 m//s .

Two trains are moving towards each other at speeds of 72kmh^-1 and 54 kmh^-1 relative to the ground. The first train sounds a whistle of frequency 600 Hz. Find the frequency of the whistle as heard by a passenger in the second train a. before the trains meet and b. after the trains have crossed each other. The speed of sound in air is 340 ms^-1

RESONANCE ENGLISH-SOUND WAVES-Exercise- 2 PART - I
  1. In a large room , a person receives direct sound waves from a source 1...

    Text Solution

    |

  2. The displacement of a medium in a sound wave is given by the equation ...

    Text Solution

    |

  3. The ratio of the speed of sound in nitrogen gas to that in helium gas ...

    Text Solution

    |

  4. Two monatomic ideal gas 1 and 2 of molecular masses m(1) and m(2) resp...

    Text Solution

    |

  5. A closed pipe resonates at its fundmental frequency of 300 Hz. Which o...

    Text Solution

    |

  6. A closed organ pipe and an open organ pipe have their first overtones...

    Text Solution

    |

  7. An open pie is suddenly closed at one end with the result that the fre...

    Text Solution

    |

  8. There is a set of four tuning forks , one with the lowest frequency vi...

    Text Solution

    |

  9. Two sound sources produce progressive waves given by y(1) = 6 cos 1...

    Text Solution

    |

  10. A fixed source of sound emitting a certain frequency appears as f(a) w...

    Text Solution

    |

  11. When a train approaches a stationary observer, the apparent frequency ...

    Text Solution

    |

  12. A police car moving at 22 m//s, chase a motoclist. The police man has ...

    Text Solution

    |

  13. A siren placed at a railway platfrom is emitted sound of frequency 5 k...

    Text Solution

    |

  14. A train moves towards a stationary observer with speed 34 m//s. The tr...

    Text Solution

    |

  15. A train blowing its whistle moves with a constant velocity v away from...

    Text Solution

    |

  16. In the case of sound waves, wind a blowing from source to reciver with...

    Text Solution

    |

  17. Two sound sources emitting sound each of wavelength lambda are fixed a...

    Text Solution

    |

  18. A car is approching a railway crossing at a speed of 72 kmph. It sound...

    Text Solution

    |

  19. Two identical source moving parallel to each other at seperation 'd' a...

    Text Solution

    |

  20. A source which is emitting sound of frequency f is initially at (-r,0)...

    Text Solution

    |