Doppler shift in frequency does not depend upon ____.
the frequency of the wave produced
the velocity of the source
the velocity of the observer
distance from the source to the listener
Source of sound of frequency 450 cycles/s is moving towards a stationary observer with 34 m/sec speed. If the speed of sound is 340 m/s, then the apparent frequency is ____.
410 cycles/s
500 cycles/s
550 cycles/s
450 cycles/s
The wavelength is 120 cm when the source is stationary. If the source is moving with relative velocity of 60 m/sec towards the observer, then the wavelength of the sound wave reaching to the observer is (velocity of sound = 330 m/s) ____.
98 cm
140 cm
120 cm
144 cm
The frequency of a whistle of an engine is 600 cycles/s is moving with the speed of 30 m/sec towards an observer. The apparent frequency is (velocity of sound = 330 m/s) ____.
600 cps
660 cps
990 cps
330 cps
A source of sound emits waves with frequency f Hz and speed V m/s. Two observers move away from this source in opposite directions each with a speed 0.2 V relative to the source. The ratio of frequencies heard by the two observers is ____.
3 : 2
2 : 3
1 : 1
4 : 10
/
An observer is moving towards the stationary source of sound, then ____.
apparent frequency is less than the real frequency
apparent frequency is greater than the real frequency
apparent frequency is equal to real frequency
only the quality of sound will change
A whistle sends out 256 waves in a second. If the whistle approaches the observer with velocity of the velocity of sound in air, the number of waves per second the observer will receive ____.
384
192
300
200
A person feels 2.5 % difference of frequency of a motor-car horn. If the motor-car is moving to the person and the velocity of sound is 320 m/s, then the velocity of car is ____.
8 m/s (approx.)
800 m/s
7 m/s
6 m/s (approx.)
A source of sound emitting a note of frequency 200 Hz moves towards an observer with a velocity v equal to the velocity of sound. If the observer also moves away from the source with the same velocity v, the apparent frequency heard by the observer is ____.
50 Hz
100 Hz
150 Hz
200 Hz
Doppler's effect will not be applicable when the velocity of sound source is ____.
equal to that of the sound velocity
less than the velocity of sound
greater than the velocity of sound
zero
An observer while going on scooter hears sound of two sirens of same frequencies from two opposite directions. If he travels along the direction of one of the siren, then he ____.
listens resonance
listens beats
will not listen sound due to destructive interference
will listen intensive sound due to constructive interference
A source of sound is traveling towards a stationary observer. The frequency of sound heard by the observer is of three times the original frequency. The velocity of sound is v m/s. The speed of source is ____.
v
3v
A sound source is moving towards a stationary observer with of the speed of sound. The ratio of apparent to real frequency is ____.
The speed of sound in air at a given temperature is 350 m/s. An engine blows whistle at a frequency of 1200 cps. It is approaching the observer with velocity 50 m/s. The apparent frequency in cps heard by the observer is ____.
600
1050
1400
2400
Suppose that the speed of sound in air at a given temperature is 400 m/s. An engine blows a whistle at 1200 Hz frequency. It is approaching an observer at the speed of 100 m/s. What is the apparent frequency as heard by the observer ____.
600 Hz
1200 Hz
1500 Hz
1600 Hz
A source of frequency 150 Hz is moving in the direction of a person with a velocity of 110 m/s. The frequency heard by the person is (speed of sound in medium = 330 m/s) ____.
225 Hz
200 Hz
150 Hz
100 Hz
The Doppler's effect is applicable for ____.
Light waves
Sound waves
Space waves
Both (a) and (b)
A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz. The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him is
(Speed of sound v = 340 m/s) ____.
9 : 8
8 : 9
1 : 1
9 : 10