Waves
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A source of sound S emitting waves of frequency 100 Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4 ms-1 at an angle of 60o with the source observer is at rest. the apparent frequency observed by the observer (velocity of sound in air 330 ms-1) is 
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100 Hz
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103 Hz
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106 Hz
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97 Hz
B.
103 Hz
Given, as a source of sound S emitting waves of frequency 100 Hz and an observer O are located at some distance. Such that, source is moving with a speed of 19.4 m/s at angle 60o with source- observer line as shown in figure
The apparent frequency heard by observer
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A speeding motorcyclist sees traffic jam ahead of him. He slows down to 36 km/hr. He finds that traffic has eased and a car moving ahead of him at 18 km/hr is honking at a frequency of 1392 Hz. If the speed of sound is 343 m/s, the frequency of the honk as heard by him will be,
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1332 Hz
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1372 Hz
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1412 Hz
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1454 Hz
C.
1412 Hz
Both the observer and the source are moving.
Therefore, using the formula of apparent frequency,

A train moving t a speed of 220 ms-1 towards a stationary object. emits a sound of frequency 1000 Hz. Some of the sound reaching the object gets reflected back to the train as echo. The frequency of the echo as detected by the driver of the train is
(speed of sound in air is 330 ms-1)
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3500 Hz
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4000 Hz
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5000 Hz
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3000 Hz
C.
5000 Hz
From Doppler's shift, we know for this case
A transverse wave os represented by y = A sin (ωt - kx). For what value of the wavelength is the wave velocity equal to the maximum particle velocity?
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π A /2
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π A
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2πA
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A
C.
2πA
Wave velocity 
A transverse wave propagating along x-axis is represented by:
where x is in metres and t is in seconds. The speed of the wave is
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m/s
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-
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8 m/s
D.
8 m/s
The standard transverse wave propagating along x-axis can be written as

The given equation is

The standard wave equation can be written as,
...(2)
where
is amplitude, k the propagation constant and
the angular frequency,
comparing the Eqs. (i) and (ii), we have

Speed of transverse wave

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