Do all EM waves travel through a vacuum?

In summary, the conversation discusses general questions about EM waves, including whether they travel through a vacuum, their speed in different mediums, and their direction of travel. The experts clarify that while EM waves technically travel through vacuums, they can also travel through other mediums such as air, and their speed can be affected by factors such as photon energy and density of matter. They also confirm that EM waves are transverse and can travel through most materials, with higher energy waves being able to penetrate further. The conversation ends with a thank you to the experts for their clarification.
  • #1
Dx
Hiya!

I have some general questions about EM waves since i am somewhat lost from reading and may have misuderstood what I read.

1) does all EM waves travel through a vacuum? if so are they the same speeds/proportional/inporportional to their frequency.

2) I now that EM waves are transverse, correct? but can they travel through pretty much anything?

3) Let's say in a vacuum, the velocity of all EM waves are they nearly 3.00 x 10^8 m/s or what?


Now for my homework question? An EM wave traveling to the east. AT one instant at a given point its E vector points straight up. what is the direction of its vector?

my answer is south unless my right hand rule i am using is actually my left hand facing in some weird direction. can you help me please or am i correct?

Thanks!
Dx :wink:
 
Physics news on Phys.org
  • #2
Originally posted by Dx
A mathematician is a blind man in a dark room looking for a black cat which isn't there

Really? How come then that a mathematician is the only one who finds the cat (=is always right)?
 
  • #3


Originally posted by Alexander
Really? How come then that a mathematician is the only one who finds the cat (=is always right)?

fair enough but how come you didn't answer my question? Please don't tell me your link is the answer to my question alexander. I wanted some better assistance but your has been appreciated, sir. Thank You!
:wink:
 
  • #4
Originally posted by Dx
1) does all EM waves travel through a vacuum?

Come on, Dx, this is an easy one. When you listen to the radio in your car, the EM waves traveled through the air (not vacuum). When someone gets an X-Ray, the EM waves travel through their body (not vacuum).

et cetera...

if so are they the same speeds/proportional/inporportional to their frequency.

Look up "index of refraction" in the chapter on EM waves. The explicit relationship should be there.

2) I now that EM waves are transverse, correct?

Correct.

but can they travel through pretty much anything?

See my answer to your first question.

3) Let's say in a vacuum, the velocity of all EM waves are they nearly 3.00 x 10^8 m/s or what?

Yes.

Now for my homework question? An EM wave traveling to the east. AT one instant at a given point its E vector points straight up. what is the direction of its vector?

my answer is south unless my right hand rule i am using is actually my left hand facing in some weird direction. can you help me please or am i correct?

Yes, you got it right.
 
  • #5
1) does all EM waves travel through a vacuum? if so are they the same speeds/proportional/inporportional to their frequency.
Well, technically they travel in the spaces between atoms in air, which are empty and hence vacuums. They all have the same speed, c in that vacuum. But when they travel through air, they are delayed by hitting stuff and being reemitted, so their overall speed is reduced.

BUT by some variants of DSR, which is a new theory going around, photon energy does affect their speed. But this is only apparent in extreme circumstances.

2) I now that EM waves are transverse, correct? but can they travel through pretty much anything?
Yes, they are transverse. But when they travel through dense matter, they tend to get dissipated/lose their energy when they bump into the particles. Usually, high energy photons - eg. gamma rays get dissipated less, and penetrate further. It is possible to shield from low energy em radiation. Close your eyes, and there is your example.

3) Let's say in a vacuum, the velocity of all EM waves are they nearly 3.00 x 10^8 m/s or what?
According to current theories, yes.
 
  • #6
Okay!

THANKS!

FZ+ and Tom, take a bow!

Thanks for the clarification. Its much appreciated and clearer now.

Dx :wink:
 

1. What are EM waves?

EM waves, short for electromagnetic waves, are a type of energy that is produced by the movement of electrically charged particles. They consist of an electric field and a magnetic field that oscillate perpendicular to each other and travel through space at the speed of light.

2. Do all EM waves travel through a vacuum?

Yes, all EM waves, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays, can travel through a vacuum. This is because they do not require a medium to propagate, unlike mechanical waves such as sound waves.

3. Can EM waves travel through other substances besides a vacuum?

Yes, EM waves can travel through various substances, such as air, water, and glass. However, the speed at which they travel may be affected by the properties of the material they are passing through, such as its density and composition.

4. Are there any other factors that can affect the speed of EM waves?

Yes, besides the material they are traveling through, the speed of EM waves can also be affected by their frequency and wavelength. In general, higher frequency waves have a shorter wavelength and can travel faster than lower frequency waves.

5. Can EM waves travel through the vacuum of outer space?

Yes, EM waves can travel through the vacuum of outer space. In fact, many of the images and data we receive from space, such as those from telescopes and satellites, are transmitted through EM waves. This is because outer space is mostly a vacuum with very few particles to obstruct the movement of these waves.

Similar threads

  • Classical Physics
2
Replies
42
Views
2K
Replies
4
Views
1K
  • Classical Physics
Replies
10
Views
818
  • Other Physics Topics
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
17
Views
1K
Replies
3
Views
765
  • Introductory Physics Homework Help
Replies
1
Views
860
  • Quantum Physics
Replies
3
Views
718
  • Introductory Physics Homework Help
Replies
12
Views
882
  • Electrical Engineering
Replies
30
Views
2K
Back
Top