Basic problem regarding doppler effect of light (E/M waves)

In summary, the conversation discusses the doppler effect of light and the formula used to calculate the frequency of observed and source light waves. The participants also mention the difficulty in solving for velocity and discuss possible solutions. The final answer for velocity is determined to be approximately 5.14 x 107 m/s, with a minor difference from the original calculation of 5.13 x 107 m/s.
  • #1
phys-lexic
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"Basic" problem regarding doppler effect of light (E/M waves)

1. At what speed would one have to move at to see a red light as green. Presume red light wavelength = 630nm and green light wavelength = 530nm.



2. f0=fs√([1+v/c]/[1-v/c])
>f0 = observed frequency
>fs = source frequency
>v = velocity relative of source and observer
>c = speed of light (3.0e8)



The Attempt at a Solution


Our professor said we only need that equation to solve the proble, we were just introduced to the topic of light, relavitiy, and polarization (our chapter is on doppler effect). I assume that to get the answer you solve for v and plug the rest in, but that's been harder than i expected. Is there another formula i can use in combination with the one given or am i just not solving for v right...? thanks.
 
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  • #2


Square both sides and solve the linear equation for v
 
  • #3


i did that... would anyone mind checking my answer?

v=[(c)(f0/fs)2-c] / [(f0/fs)2+1]

and my final answer for v was 5.14 x 107 m/s, towards the source because the wavelength shifts from the source, 630nm, to that observed, 530nm, a blue shift...?
 
  • #4


I got v = 5.13 x 107 m/s but that's a minor detail =) since the formula is the same
 
  • #5


sweet... thanks
 

1. What is the Doppler effect of light?

The Doppler effect of light, also known as the Doppler shift, is the apparent change in the frequency or wavelength of electromagnetic waves (such as light) due to the relative motion between the source of the waves and the observer.

2. How does the Doppler effect of light work?

The Doppler effect of light works by altering the wavelength of the light waves as the source of the waves moves closer or farther away from the observer. This results in a shift in the color of the light, with waves appearing shorter and bluer when the source moves towards the observer, and longer and redder when the source moves away from the observer.

3. What causes the Doppler effect of light?

The Doppler effect of light is caused by the relative motion between the source of the light waves and the observer. This can occur when the source is moving towards or away from the observer, or when the observer is moving towards or away from the source. The effect is also observed in cases where the source and observer are both in motion.

4. How is the Doppler effect of light used in science?

The Doppler effect of light is used in various fields of science, including astronomy, meteorology, and medical imaging. In astronomy, it is used to measure the velocity and distance of celestial objects, while in meteorology it is used to track the movement of storms. In medical imaging, it is used to create images of internal body structures, such as in ultrasounds.

5. Can the Doppler effect of light be observed in everyday life?

Yes, the Doppler effect of light can be observed in everyday life. For example, the sound of a passing ambulance or train will appear to change pitch as it approaches and then moves away from the observer, similar to the change in color of light waves due to the Doppler effect. Additionally, the redshift and blueshift of stars and galaxies, which is caused by the Doppler effect of light, can also be observed in everyday life with the use of telescopes.

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