Speed inorder to shift green light to blue light?

In summary, the conversation discusses using the Doppler effect to determine the speed at which a green laser light would change into low energy blue light when shined from a moving jet or spaceship. The formula for the relativistic Doppler effect is provided and it is suggested to solve for β to find the speed. The conversation also mentions converting wavelength to frequency and how the formula can be used to determine the frequency shift seen by an observer when the light source is moving towards them.
  • #1
Moviemann345
24
0
Hypothetically if your in a jet or spaceship & are shining a green laser pen out the window how fast must you travel to cause the green light (570 nm) to change into low energy blue light (475 nm)
 
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  • #2
Look up the Doppler effect.
 
  • #3
fo = fv/(v ± vs)? This isn't a homework problem & I am not in a physics class, I was just curious
 
  • #4
Moviemann345 said:
fo = fv/(v ± vs)? This isn't a homework problem & I am not in a physics class, I was just curious
You need to use the relativistic Doppler formula:

[tex]f_o = f_s \sqrt{\frac{1 + \beta}{1 - \beta}}[/tex]

where β = v/c

Solve for β, then you'll have the speed. To convert wavelength to frequency, use c = fλ.

This tells you the frequency shift seen by an observer when the light source moves toward him at speed v.
 
  • #5
Oh ok thanks I'll try it out
 

1. How does speed affect the color of light?

As an object moves at a faster speed, its emitted light shifts towards the blue end of the visible light spectrum. This is known as the Doppler effect, where the wavelength of light appears shorter as an object moves towards an observer.

2. Can the speed of an object change the color of light it emits?

Yes, the speed of an object can change the color of light it emits. As an object's speed increases, the wavelength of light it emits becomes shorter, resulting in a shift towards the blue end of the spectrum. This is also true for objects moving away from an observer, as the light emitted will shift towards the red end of the spectrum.

3. Is the shift in light color always noticeable when an object is moving at high speeds?

The shift in light color may not always be noticeable when an object is moving at high speeds. This is because the Doppler effect is only significant for objects moving at very high speeds, such as those close to the speed of light. For objects moving at slower speeds, the shift in light color may be too small to detect with the naked eye.

4. How is the color of light affected when an object moves at the speed of light?

As an object approaches the speed of light, the shift in light color becomes more significant. At the speed of light, the Doppler effect causes the wavelength of light to become infinitely short, resulting in a shift towards the ultraviolet end of the spectrum. However, objects with mass cannot reach the speed of light, according to Einstein's theory of relativity.

5. Are there any other factors besides speed that can affect the color of light?

Yes, besides speed, the color of light can also be affected by the object's temperature and the medium through which the light is passing. As an object's temperature increases, the color of its emitted light shifts towards the blue end of the spectrum. Additionally, light passing through different mediums, such as water or air, may also cause a shift in color due to refraction.

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