Doppler effect Definition and 486 Threads

Homework Statement A light source moves away from an observer at a speed vs that is small compared to c. show that the fractional shift in the observed wavelength can be approximated by \frac{\Delta \lambda}{\lambda} \approx \frac{v_2 }{c} Homework Equations f' = \frac{\sqrt{1+ \frac{v}{c} }...

Hello, what is referred to that every moving body has an associate wavelength ? thank you

Homework Statement Police radar detects the speed of a car as follows: Microwaves of a precisely known frequency are broadcast toward the car. The moving car reflects the waves with a doppler shift. The reflected waves are received and combined with an attenuated version of the tansmitted wave...

Homework Statement An engineer at an underwater military station listens for submarines by sending an ultrasound sonar ping that has a frequency of 3.75 MHz. A second ping returns with a frequency of 3.80 MHz, indicating that the object is now moving. What is the object’s velocity? In...

I thought the speed of light was constant independent of the motions of the observer and light source. So I don't understand how the doppler (blue-red) shift can be observed on incomming or receding astronomical light sources? Speed also varies depending on the medium it travels through, so...

Homework Statement A source of sound emits waves of wavelength λ, period T and speed v when at rest. The source moves away from a stationary observer at speed V, relative to the observer. The wavelength of the sound waves, as measured by the observer is A. λ + vT B. λ - vT C. λ + VT D...

Homework Statement An observer is moving to the right. A source is moving to the left. There is a wind moving to the right. What is the observed frequency? I had a quiz and this came up. I'm not sure if I did it right. Homework Equations f'=f(v±(vl-vw))/(v±(vs-vw)) The Attempt...

If I have a matter wave (for example, electron waves in a electronic microscope) at a given wavelength λ, and I move with respect (towards) them at speed v, I will measure a Doppler shift in the wave given by: \frac{1}{{\lambda '}} = \frac{1}{{\lambda '}}\left( {1 + \frac{v}{{v_e }}} \right)...

Homework Statement I attatched 2 images, the problem, and my work (including the formula needed)This "double shift" is what's getting me. Is it going 2% towards the object, and 2% from it? Or I'm I suppose to use 2 functions:F'=(f+xf) and F'=(f+yf) where x + y = 0.04? Homework Equations See...

Hi, I'm confused about how Doppler effect shifts the wavelength of light depending on the speed of the emitter. It makes sense from a classical point of view that the wavelength should shift. However, when I consider that light comes from photons, quantized energy, any shift in frequency...

Homework Statement Imagine you are observing a spacecraft moving in a circular orbit of radius 128,000 km around a distant planet. You happen to be located in the plane of the spacecraft 's orbit. You find that the spacecraft 's radio signal varies periodically in wavelength between...

If I am stationary and a sound source moves towards me at a constant velocity, I will hear it (the sound) increase in frequency until it is adjacent to me and then as it moves away from me, I will hear a decreasing frequency. Fundamental stuff right? It works with radio waves and light which is...

Homework Statement The light from galaxy NGC 221 consists of a recognizable spectrum of wavelengths. However, all are shifted to the shorter wavelength end of the spectrum. In Particular, the calcium "line" ordinarily observed at 396.85nm is observed at 396.58nm. (a) is this galaxy moving...

Could "Redshift" not result from the Doppler effect? Redshift is the astronomical phenomenon where galaxies and other far-away objects appear shifted to the "red" side of the visible light spectrum. The farther an object is from us, the more pronounced this shift is. This phenomenon is most...

Homework Statement A car and a bicycle are traveling directly toward each other at different speeds. The car horn has a frequency of 440Hz, and the car is traveling at 15.0m/s. The cyclist hears a sound of frequency 467Hz. The velocity of sound in air is 343m/s. i) Calculate the frequency of...

Could someone explain how the relativity of simultaneity and the doppler effect are different?

If the doppler effect is the changing if wavelengths due to movement of a light source (In reference to light of course), does this mean the distance between the wavefront and the source changes at a speed DIFFERENT from C? doesn't this mean that if the observer is in the plane of the source the...

Hi all. I am asking for some help with getting a physical intuition for the following situation: Consider an observer and source, at rest. The source emits sound waves of a particular frequency, 'f'. Letting the medium (air for example) between the source and the observer move with a particular...

I tried to wiki this,which stated relativistic doppler effect takes time dilution into account,but the analogy/example given was not related to time dilution..can anyone summarise both with a practical situation or a useful link for it Thanks in advance

Homework Statement Radar is used to measure the speed of passing vehicles. A stationary radar gun emits EM radiation, a proportion of which is reflected from the target vehicle which is moving away from the gun at 'u' ms^-1. a)State the frequency at the target vehicle (f.tar) in terms of...

When a car is approaching it has a higher frequency and shorter wavelength. When it has passed sound waves are a lower frequency due to a longer wavelength. Question: Does the higher frequency contain more energy when compared to the low frequency? IF IT DOES NOT, then could it possibly be...

Consider a stationary observer and an emitter of light radiation that may be either receding or approaching at a variety of nonrelativistic velocities, with the velocity of the emitter having only a radial component and no transverse component. I was wondering whether the Doppler Effect...

A source and a receiver is at rest with each other. Source emits some couple of light pulses, and stops emitting more. 1. The pulses is not reached to the receiver yet, and source starts moving. Does the receiver experience doppler effect with the emitted pulses? 2. The pulses is not...

Assume a object in motion emits a beam of light at an observer. The observer detects a frequency that is higher than the original frequency. That is the measured energy of the photon by this observer is higher than it was while emitting. How to account for this extra energy? thanks, kalpak

Homework Statement You are cruising to Jupiter at the posted speed limit of 0.1c when suddenly a daredevil passes you, going in the same direction, at 0.3c. At what wavelength does your rocket cruiser's light detecter "see" his red tail lights? Is this wavelength ultraviolet, visible, or...

To find out how fast you would have to be going in order to to see a green light when the light is infact red what doppler equation would you use. I used f = ((c+v)/c)*f0. Is this wrong, if so why?

From the special relativity theory , for explaining the red-shifting of a photon, that has been red-shifted, is the following: point O: origin point of emitted photo, in Galaxy GlxO point R: receiving point of photon, in Galaxy GlxR GlxO, O ---------->----------------R, GlxR Suppose...

Homework Statement A detector initially moves at a constant velocity directly toward a stationary sound source and then (after passing it) directly from it. The emitted frequency is f. During the approach the detected frequency is f'app and during the recession it is f'rec. If the...

Homework Statement There is a question asking the frequency of a distant location from two rotating speakers which are attached to the both ends of a meter ruler. The ruler is rotating ar 7 rounds per second and A speaker has a frequency of 500Hz. At the given time they are in a position which...

does doppler effect affect ENERGY of photon?? i have tried to make the question as clear as possible,but in the process,have made it a bit too long. i request you to be patient- suppose a source is emitting a photon after equal intervals of time.an observer,who was initially at rest w.r.t the...

When I ask for differences I am not meaning mathematical ones since that it is obvious: We have a phenomenon p, p can be described by Galilean Relativity (GR) and by Einsten Relativity (ER). ER(p)!=GR(p) The math expression that describes this phenomenon is different. Then the doppler...

Homework Statement A woman is riding a bicycle at 18.0 m/s along a straight road that runs parallel to and right next to some railroad tracks. She hears the whistle of a train that is behind. The frequency emitted by the train is 840 Hz, but the frequency the woman hears is 778 Hz. Take the...

Homework Statement A policeman detects a drop of 10% in the pitch of the horn of a motor car as it crosses him. If the velocity of sound is 330ms^-1, calculate the speed of the car. Homework Equations f2 = f1 [v - v(listener)]/[v - v(source)] where f2 = apparent frequency f1 =...

The image shows four points. "A" is source of light and "B" is receiver, and "a" and "b" represents co-ordinate points. "A" is moving with constant speed to "B". "B" feels doppler effect. If "B" moving with constant speed to "A", then also "B" feels doppler effect. Statement 1: This two...

Homework Statement A microphone is attached to a spring that is suspended from the ceiling. Directly below on the floor is a stationary 540-Hz source of sound. The microphone vibrates up and down in simple harmonic motion with a period of 2.20 s. The difference between the maximum and minimum...

Homework Statement Two auto-mobiles are driving on the same road in opposite directions. The speed of the first auto-mobile is 90.0 km/h and that of the second is 60 km/h. The horns of both auto-mobiles emit tons of frequency 524 Hz. Calculate the frequency that the driver of each...

Lets say we have some particle A 1m above the ground. Let it has velocity v. Also let's consider gravitons like the reason/mechanism of the gravitation. Let gravitons moves away from the Earth with velocity c. Now let's consider the differences between two cases: 1 when particle A moves down...

When a source emitting a sound of a specific frequency moves towards the face of a cliff at a speed. The frequency of the sound that reaches the cliff is for sure not the same as the frequency emitted from the source due to doppler effect. Will the frequency of the sound reflected by the cliff...

So I'm having a hard time getting the second part of the problem, so could anyone help me An ambulance travels down a highway at a speed of 65.0 mi/h, its siren emitting sound at a frequency of 4.10 102 Hz. Take the speed of sound in air to be v = 345 m/s. What frequency is heard by a...

The Doppler Effect -- frequency of a bat reflected on wall Homework Statement A bat flies toward a wall, emitting a steady sound with a frequency of 22.0 kHz. This bat hears its own sound plus the sound reflected by the wall. How fast should the bat fly to hear a beat frequency of 190...

Homework Statement A sound source emits sounds of frequency 210 Hz that travel through still air at 340 m/s. The listener moves at 85 m/s relative to still air toward the stationary source. What is the wavelength of the sound between the source and the listener? Homework Equations f' = f[1+...

Hello everyone! I need some help with a Doppler effect/relative motion question. Homework Statement A whistle with a frequency of 1200 Hz is traveling south at a velocity of 30.0 m/s. You are traveling north away from the whistle at a speed if 18.0 m/s. If the speed of sound is 340 m/s, what...

Homework Statement The frequency ratio of a semitone interval on the equally tempered scale is 2 1/12. A) Show that the ratio is 1.059 B) Find the speed of an automobile passing a listener in still air if the pitch of the car's horn drops a semitone between the times when the car is...

Hello everyone, I'm trying to calculate the doppler shift in frequency of a moving source. I'm approaching the problem from two different frames of reference and getting inconsistent results. what am I missing here? consider the special case of transverse doppler effect (θ=π/2). light...

As you know,the formula for doppler effect is: f^{'}=\frac{v-v_{o}}{v-v_{s}}f relativity suggests(at least I think) that f^{'} for v_{o}=u and v_{s}=0 should be the same with f^{'} for v_{o}=0 and v_{s}=-u,otherwise,there will be a way for the listener to know that which one,sound...

I noticed that once I was talking to a friend close to me and then a vehicle passed by with a huge sound and then I merely heard what he said. Can someone explain me why ? even though that friend was close to me ? Does it have any connection with the Doppler effect ?

Homework Statement Superman is carrying a red lantern with wavelength 650nm. He flies toward you at a speed of 2.7x108 m/s. What is the observed wavelength?Homework Equations f'=\frac{f}{\left(1-\frac{v_s}{v}\right)} and f=\frac{c}{\lambda}The Attempt at a Solution I used the equation...

Homework Statement Superman has a blue light of wavelength 480nm. How fast must he fly away from you so that his light appears orange, with a wavelength of 600nm?Homework Equations f'=\frac{f}{\left(1+\frac{v_s}{v}\right)} and f=\frac{c}{\lambda}The Attempt at a Solution I used the equation...

in the equation at: http://en.wikipedia.org/wiki/Radar#Doppler_effect what does the v stand for? it is not explained, only vobs and vs are explained. Thanks.

Homework Statement A physics student drops a vibrating 421 Hz tuning fork down the elevator shaft of a tall building. The temperature in the shaft is 20 °C. When the student hears a frequency of 392 Hz, how far has the tuning fork fallen? fS = 421 Hz fL = 392 Hz VSOUND = 343 m/s...