Doppler Effect
WAVES

173060 A car moving at a velocity of $17 \mathrm{~ms}^{-1}$ towards an approaching bus that blows a horn at a frequency of $640 \mathrm{~Hz}$ on a straight track. The frequency of this horn appears to be $680 \mathrm{~Hz}$ to the car driver. If the velocity of sound in air is $340 \mathrm{~ms}^{-1}$, then the velocity of the approaching bus is

1 $2 \mathrm{~ms}^{-1}$
2 $4 \mathrm{~ms}^{-1}$
3 $8 \mathrm{~ms}^{-1}$
4 $10 \mathrm{~ms}^{-1}$
WAVES

173061 A train approaching a railway platform with a speed of $20 \mathrm{~ms}^{-1}$ starts blowing the whistle. Speed of sound in air is $340 \mathrm{~ms}^{-1}$. If the frequency of the emitted sound from the whistle is $640 \mathrm{~Hz}$, the frequency of sound to a person standing on the platform will appear to be

1 $600 \mathrm{~Hz}$
2 $640 \mathrm{~Hz}$
3 $680 \mathrm{~Hz}$
4 $720 \mathrm{~Hz}$
WAVES

173062 A train is moving with a constant speed along a circular track. The engine of the train emits a sound of frequency $f$. The frequency heard by the guard at rear end of the train is.

1 Less then $f$
2 equal to $f$
3 is greater than $f$
4 may be greater than, less than or equal to $f$ depending on the factors like speed of train, length of train and radius of circular track
WAVES

173063 Two sources are at a finite distance apart. They emit sound of wavelength $\lambda$. An observer situated between them on line joining the sources, approaches towards on source with speed $u$, then the number of beats heard per second by observe will be.

1 $\frac{2 u}{\lambda}$
2 $\frac{u}{\lambda}$
3 $\frac{u}{2 \lambda}$
4 $\frac{\lambda}{u}$
WAVES

173060 A car moving at a velocity of $17 \mathrm{~ms}^{-1}$ towards an approaching bus that blows a horn at a frequency of $640 \mathrm{~Hz}$ on a straight track. The frequency of this horn appears to be $680 \mathrm{~Hz}$ to the car driver. If the velocity of sound in air is $340 \mathrm{~ms}^{-1}$, then the velocity of the approaching bus is

1 $2 \mathrm{~ms}^{-1}$
2 $4 \mathrm{~ms}^{-1}$
3 $8 \mathrm{~ms}^{-1}$
4 $10 \mathrm{~ms}^{-1}$
WAVES

173061 A train approaching a railway platform with a speed of $20 \mathrm{~ms}^{-1}$ starts blowing the whistle. Speed of sound in air is $340 \mathrm{~ms}^{-1}$. If the frequency of the emitted sound from the whistle is $640 \mathrm{~Hz}$, the frequency of sound to a person standing on the platform will appear to be

1 $600 \mathrm{~Hz}$
2 $640 \mathrm{~Hz}$
3 $680 \mathrm{~Hz}$
4 $720 \mathrm{~Hz}$
WAVES

173062 A train is moving with a constant speed along a circular track. The engine of the train emits a sound of frequency $f$. The frequency heard by the guard at rear end of the train is.

1 Less then $f$
2 equal to $f$
3 is greater than $f$
4 may be greater than, less than or equal to $f$ depending on the factors like speed of train, length of train and radius of circular track
WAVES

173063 Two sources are at a finite distance apart. They emit sound of wavelength $\lambda$. An observer situated between them on line joining the sources, approaches towards on source with speed $u$, then the number of beats heard per second by observe will be.

1 $\frac{2 u}{\lambda}$
2 $\frac{u}{\lambda}$
3 $\frac{u}{2 \lambda}$
4 $\frac{\lambda}{u}$
WAVES

173060 A car moving at a velocity of $17 \mathrm{~ms}^{-1}$ towards an approaching bus that blows a horn at a frequency of $640 \mathrm{~Hz}$ on a straight track. The frequency of this horn appears to be $680 \mathrm{~Hz}$ to the car driver. If the velocity of sound in air is $340 \mathrm{~ms}^{-1}$, then the velocity of the approaching bus is

1 $2 \mathrm{~ms}^{-1}$
2 $4 \mathrm{~ms}^{-1}$
3 $8 \mathrm{~ms}^{-1}$
4 $10 \mathrm{~ms}^{-1}$
WAVES

173061 A train approaching a railway platform with a speed of $20 \mathrm{~ms}^{-1}$ starts blowing the whistle. Speed of sound in air is $340 \mathrm{~ms}^{-1}$. If the frequency of the emitted sound from the whistle is $640 \mathrm{~Hz}$, the frequency of sound to a person standing on the platform will appear to be

1 $600 \mathrm{~Hz}$
2 $640 \mathrm{~Hz}$
3 $680 \mathrm{~Hz}$
4 $720 \mathrm{~Hz}$
WAVES

173062 A train is moving with a constant speed along a circular track. The engine of the train emits a sound of frequency $f$. The frequency heard by the guard at rear end of the train is.

1 Less then $f$
2 equal to $f$
3 is greater than $f$
4 may be greater than, less than or equal to $f$ depending on the factors like speed of train, length of train and radius of circular track
WAVES

173063 Two sources are at a finite distance apart. They emit sound of wavelength $\lambda$. An observer situated between them on line joining the sources, approaches towards on source with speed $u$, then the number of beats heard per second by observe will be.

1 $\frac{2 u}{\lambda}$
2 $\frac{u}{\lambda}$
3 $\frac{u}{2 \lambda}$
4 $\frac{\lambda}{u}$
WAVES

173060 A car moving at a velocity of $17 \mathrm{~ms}^{-1}$ towards an approaching bus that blows a horn at a frequency of $640 \mathrm{~Hz}$ on a straight track. The frequency of this horn appears to be $680 \mathrm{~Hz}$ to the car driver. If the velocity of sound in air is $340 \mathrm{~ms}^{-1}$, then the velocity of the approaching bus is

1 $2 \mathrm{~ms}^{-1}$
2 $4 \mathrm{~ms}^{-1}$
3 $8 \mathrm{~ms}^{-1}$
4 $10 \mathrm{~ms}^{-1}$
WAVES

173061 A train approaching a railway platform with a speed of $20 \mathrm{~ms}^{-1}$ starts blowing the whistle. Speed of sound in air is $340 \mathrm{~ms}^{-1}$. If the frequency of the emitted sound from the whistle is $640 \mathrm{~Hz}$, the frequency of sound to a person standing on the platform will appear to be

1 $600 \mathrm{~Hz}$
2 $640 \mathrm{~Hz}$
3 $680 \mathrm{~Hz}$
4 $720 \mathrm{~Hz}$
WAVES

173062 A train is moving with a constant speed along a circular track. The engine of the train emits a sound of frequency $f$. The frequency heard by the guard at rear end of the train is.

1 Less then $f$
2 equal to $f$
3 is greater than $f$
4 may be greater than, less than or equal to $f$ depending on the factors like speed of train, length of train and radius of circular track
WAVES

173063 Two sources are at a finite distance apart. They emit sound of wavelength $\lambda$. An observer situated between them on line joining the sources, approaches towards on source with speed $u$, then the number of beats heard per second by observe will be.

1 $\frac{2 u}{\lambda}$
2 $\frac{u}{\lambda}$
3 $\frac{u}{2 \lambda}$
4 $\frac{\lambda}{u}$