Home
Class 11
PHYSICS
A sound wave of frequency f travels hori...

A sound wave of frequency `f` travels horizontally to the right. It is reflected from a large vertical plane surface moving to left with a speed `v`. The speed of sound in medium is `C`

A

The number of wave striking the surface per second is `f (c+v)/(c)`

B

The wavelength of reflected wave is `(c(c-v))/(f(c+v))`

C

The frequency of the reflected wave is `"f"((c+v))/((c-v))`

D

The number of beats heard by a stationary listener to the left of the reflecting surface is `(vf)/(c-v)`

Text Solution

Verified by Experts

The correct Answer is:
A, B, C
No of wave striking the surface `f = f((c+v)/(c))`
`f=f ((c)/(c-v)) = f((c+v)/(c-v))`
`lamda = (c)/(f') = (c)/(f) ((c-v)/(c+v))`
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • WAVES AND OSCILLATIONS

    ALLEN |Exercise Part-1(Exercise-03)|31 Videos

  • WAVES AND OSCILLATIONS

    ALLEN |Exercise Part-1(Exercise-04)[A]|29 Videos

  • WAVES AND OSCILLATIONS

    ALLEN |Exercise Part-1(Exercise-01)|53 Videos

  • SEMICONDUCTORS

    ALLEN |Exercise Part-3(Exercise-4)|50 Videos

Similar Questions

Explore conceptually related problems

A charge +2q moves vertically upwards with speed v , a second charge -q moves horizontally to the right with the same speed v , and a third charge +q moves horizonatlly to the right with the same speed v . The point P is located a perpendicular distance a away from each charge as shown in the figure. The magnetic field at point P is

A bat is flitting about in a cave, navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is 40kHz. During one fast swoop directly toward a flat wall surface, the bat is moving at 0.03 times the speed of sound in air. What frequency does the bat hear reflected off the wall?

Knowledge Check

  • A train, standingin a station yard, blows a whistle of frequency 400 Hz in still air. The wind starts blowing in the direction from the yard to the station with a speed of 10 m/s. Given that the speed of sound in still air is 340 m/s. Then ..

    A
    the frequency of sound as heard by an observer standing on the platform is 400 Hz.
    B
    the speed of sound for the observer standing on the platform is 350 m/s.
    C
    the frequency of sound as heard by the observer standing on the platform will increase.
    D
    the frequency of sound as heard by the observer standing on the platform will decrease.

  • Sound waves of wavelength lamda travelling in a medium with a speed of v m/s enter into another medium where its speed is 2v m/s. Wavelength of sound waves in the second medium is

    A
    `lamda`
    B
    `(lamda)/(2)`
    C
    `2lamda`
    D
    `4lamda`

    • Similar Questions

    Explore conceptually related problems

    A bat is flitting about in a cave, navigating via ultrasonic beeps. Assume that the sound emission frequency of the bat is 40 kHz. During one fast swoop directly toward a flat wall surface, the bat is moving at 0.03 times the speed of sound in air. What frequency does the bat hear reflected off the wall ?

    An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s^(-1) .

    A band playing music at a frequency f is moving towards a wall at a speed v_(b) . A motorist is following the band with a speed v_(m) . If v is the speed of sound, obtain an expression for the beat frequency heard by the motorist.

    A bat emits ultrasonic sound of frequency 100 kHz in air. If this sound meets a water surface, the wavelengths of the reflected and transmitted sound are (Speed of sound in air = 340 m s^(-1) and in water = 1500 m s^(-1) )

    One engine whistles with a sound of frequency 660 Hz while moving towards a cliff with a speed 10 m/s. Find frequency of sound reflected from this cliff as heard by driver of this engine. Speed of sound in air is 340 m/s.

    A bat emits ultrasonic sound of frequency 1000 kHz in air. If the sound meets a water surface, what is the wavelength of (a) the reflected sound, (b) the transmitted sound ? Speed of sound in air is 340 ms ^(-1) and in water 1486 ms ^(-1).

    Home
    Profile