Special Relativity - Light wave crest

In summary: The Attempt at a SolutionI am not sure how to really apply both galilean and lorentz to this... i know that for the first question total wave crests = wavelength/distance[/QUOTE]That's a bit vague. Can you give a more specific example?But, you'll need to be careful; the wavefronts are spherical, but the motion is only in the x-direction. What happens to each component of the wavevector? How is the wavelength related to these components?I know it is goofy to think of light being so slow - but if that were true... when I walk by you I would be contracting at an alarming rate!
  • #1
2x2lcallingcq
9
0

Homework Statement


Assume that the speed of light is 3.0m/s - an observer S observes a series of spherical light waves emanating from their fixed origin at time t=0 according to S. The wavelength of the light as seen by S is 1.0m. Another reference frame S' is moving in the positive x-direction of S at a speed of 2.8m. The clocks of s and s' are synched at t=o when the origins are also coincident. X' axis of S' is parallel to and moves directly over the X axis of S. The lengths of the axes of both s and s' will be 20 meters long.

calc all the emitted wave crests as seen by S after time t=1.0s has elapsed (According to S) hint- determine the general equation of motion

using Galilean transform. calc the geometrical structure of ALL emitted wave crests seen by S' after t'=2.5s

Using Lorentz transform. calc the ' ' ' structure of ALL emitted wave crests seen by S' after t'=2.5s


Homework Equations


Galilean = http://en.wikipedia.org/wiki/Galilean_transformation
Lorentz = http://en.wikipedia.org/wiki/Lorentz_transformation


The Attempt at a Solution


I am not sure how to really apply both galilean and lorentz to this...
i know that for the first question total wave crests = wavelength/distance
 
Physics news on Phys.org
  • #2
Hi 2x2lcallingcq, welcome to PF! :smile:

2x2lcallingcq said:
Assume that the speed of light is 3.0m/s

That's an odd assumption to make! Are you sure it doesn't say, "Assume that the speed of light is 3.0 × 108 m/s"?

I am not sure how to really apply both galilean and lorentz to this...
i know that for the first question total wave crests = wavelength/distance[/QUOTE]

Well, if you can calculate the wavelength and distance in S' using Galilean/Lorentz transformations, then surely you can calculate the number of wavecrests in S', right?:wink:

But, you'll need to be careful; the wavefronts are spherical, but the motion is only in the x-direction. What happens to each component of the wavevector? How is the wavelength related to these components?
 
  • #3
I know it is goofy to think of light being so slow - but if that were true... when I walk by you I would be contracting at an alarming rate!
 
  • #4
ALSO i should have mentioned that the only direction that is being measured is in the X and Y direction not the Z
 
  • #5
Also how could i go about using the amazing transformations to accomplish this? I don't exactly know how to use the reference frames for waves of light... I could do it if i were measuring boxes or points on a plain but ...
 
  • #6
Are you familiar with the general equation of a plane wave?
 
  • #7
Like the y= cos((wt-k)(r+not)) that kind, ehhh? :)
 
  • #8
Sort of, but you are looking for an equation for the electric (or magnetic) field [itex]\textbf{E}(\textbf{r},t)[/itex]...look up "electromagnetic plane wave" in your text or on wikipedia...
 

What is special relativity?

Special relativity is a theory in physics that explains the relationship between space and time, particularly how they are affected by the speed of light and the laws of physics. It was developed by Albert Einstein in the early 20th century and has been confirmed by numerous experiments.

What is a light wave crest?

A light wave crest is the highest point of a light wave, where the amplitude (or height) of the wave is at its maximum. This is also known as the peak of the wave and can be seen as the brightest part of a light wave.

How does special relativity relate to light wave crests?

Special relativity states that the speed of light in a vacuum is constant and is the same for all observers, regardless of their relative motion. This means that the frequency (or number of wave crests passing a point per second) and wavelength (distance between wave crests) of a light wave will remain the same for all observers, even if they are moving at different speeds.

Can light wave crests be affected by gravity?

Yes, according to general relativity (which extends special relativity to include gravity), light wave crests can be affected by gravity. This is because gravity can cause space and time to be distorted, which in turn can affect the speed and path of light waves.

What practical applications does special relativity have?

Special relativity has many practical applications, including GPS technology, nuclear energy, and particle accelerators. It also plays a crucial role in our understanding of the universe, as it is a fundamental part of the theory of gravity and the behavior of matter and energy at high speeds.

Similar threads

  • Advanced Physics Homework Help
Replies
2
Views
1K
  • Special and General Relativity
Replies
5
Views
736
  • Advanced Physics Homework Help
Replies
9
Views
1K
  • Advanced Physics Homework Help
Replies
4
Views
305
  • Introductory Physics Homework Help
2
Replies
35
Views
3K
  • Introductory Physics Homework Help
Replies
6
Views
756
  • Special and General Relativity
Replies
20
Views
747
  • Advanced Physics Homework Help
Replies
1
Views
880
  • Special and General Relativity
5
Replies
146
Views
6K
  • Introductory Physics Homework Help
Replies
13
Views
1K
Back
Top