Advertisements
Advertisements
प्रश्न
What is meant by the Doppler effect?
Advertisements
उत्तर
When the source and the observer are in relative motion with respect to each other and to the medium in which sound is propagated, the frequency of the sound wave observed is different from the frequency of the source. This phenomenon is called Doppler Effect.
APPEARS IN
संबंधित प्रश्न
A narrow sound pulse (for example, a short pip by a whistle) is sent across a medium. (a) Does the pulse have a definite (i) frequency, (ii) wavelength, (iii) speed of propagation? (b) If the pulse rate is 1 after every 20 s, (that is the whistle is blown for a split of second after every 20 s), is the frequency of the note produced by the whistle equal to 1/20 or 0.05 Hz
The sound emitted from the siren of an ambulance has a frequency of 1500 Hz. The speed of sound is 340 m/s. Calculate the difference in frequencies heard by a stationary observer if the ambulance initially travels towards and then away from the observer at a speed of 30 m/s.
The speed of a wave in a certain medium is 900 m/s. If 3000 waves passes over a certain point of the medium in 2 minutes, then compute its wavelength?
A source of sound is moving with constant velocity of 30 mis emitting a note of frequency 256 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 in air = 330 m/s)
The pitch of the whistle of an engine appears to drop to`(5/6)^"th"` of original value when it passes a stationary observer. If the speed of sound in air is 350 m/s then the speed of engine is ____________.
A car sounding a horn of frequency 1000 Hz passes au observer. The ratio of frequencies of the horn noted by the observer before and after passing of the car is 11 : 9. If the speed of sound is 'V', the speed of the car is ______.
A sitar wire is replaced by another wire of same length and material but of three times the earlier radius. If the tension in the wire remains the same, by what factor will the frequency change?
A source and a detector move away from each other in absence of wind with a speed of 20 m/s with respect to the ground. If the detector detects a frequency of 1800 Hz of the sound coming from the source, then the original frequency of the source considering the speed of sound in air 340 m/s will be ______ Hz.
A train moving at 25 m/s emits a whistle of frequency 200 Hz. If the speed of sound in air is 340 m/s, find the frequency observed by a stationary observer.
- if the observer is in front of the source.
- if the observer is behind the train.
The frequency of echo will be ______ Hz if the train blowing a whistle of frequency 320 Hz is moving with a velocity of 36 km/h towards a hill from which an echo is heard by the train driver. The velocity of sound in air is 330 m/s.
