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प्रश्न
The change in frequency due to Doppler effect does not depend on
विकल्प
the speed of the source
the speed of the observer
the frequency of the source
separation between the source and the observer.
उत्तर
separation between the source and the observer \[v_0 = \left( \frac{v \pm u_0}{v \pm u_s} \right) v_s\]
It is clear from the equation that the change in frequency due to Doppler effect depends only on the relative motion and not on the distance between the source and the observer.
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संबंधित प्रश्न
Answer briefly.
State the expression for apparent frequency when the source is stationary and the listener is
- moving towards the source
- moving away from the source
Answer briefly.
State the expression for apparent frequency when source of sound and listener are
- moving towards each other
- moving away from each other
Solve the following problem.
A police car travels towards a stationary observer at a speed of 15 m/s. The siren on the car emits a sound of frequency 250 Hz. Calculate the recorded frequency. The speed of sound is 340 m/s.
Explain red shift and blue shift in Doppler Effect.
Discuss the following case-
Observer in motion and Source at rest.
- Observer moves towards Source
- Observer resides away from the Source
Consider a mixture of 2 mol of helium and 4 mol of oxygen. Compute the speed of sound in this gas mixture at 300 K.
A ship in a sea sends SONAR waves straight down into the seawater from the bottom of the ship. The signal reflects from the deep bottom bedrock and returns to the ship after 3.5 s. After the ship moves to 100 km it sends another signal which returns back after 2 s. Calculate the depth of the sea in each case and also compute the difference in height between two cases.
How do animals sense impending danger of hurricane?
Two cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by the driver of the second car is [velocity of sound 340 m/s]: ____________.
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)
A bus is moving with a velocity of 5 m is towards a wall. The driver blows the horn of frequency 165 Hz. If the speed of sound in air is 335 m is, then after reflection of sound wave, the number of beats per second heard by the passengers in the bus will be ______.
An observer moves towards a stationary source of sound with a velocity one-fifth of the velocity of sound. The percentage increase in the apparent frequency heard by the observer will be ______.
A source of sound is moving towards a stationary observer with velocity 'Vs' and then moves away with velocity 'Vs'. Assume that the medium through which the sound waves travel is at rest, if 'V' is the velocity of sound and 'n' is the frequency emitted by the source, then the difference between the apparent frequencies heard by the observer 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 train standing at the outer signal of a railway station blows a whistle of frequency 400 Hz still air. The train begins to move with a speed of 10 ms–1 towards the platform. What is the frequency of the sound for an observer standing on the platform? (sound velocity in air = 330 ms–1)
A racing car moving towards a cliff sounds its horn. The sound reflected from the cliff has a pitch one octave higher than the actual sound of the horn. If V is the velocity of sound, the velocity of the car is ______.
A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with speed v ms-1. The velocity of sound in air is 300 ms-1. If the person can hear frequencies up to a maximum of 10,000 HZ, the maximum value of v up to which he can hear the whistle is ______.
