Electromagnetic waves

In summary, when an electromagnetic wave passes from one material into another with a higher index of refraction, its frequency remains unchanged, but its wavelength changes. This difference in wavelength can cause effects such as diffraction and bending around objects, but the frequency of the wave remains constant.
  • #1
Lennox786
7
0

Homework Statement


I have to re-write the following statement because it is either incomplete or false. When an electromagnetic waves passes from one material into another with a higher index of refraction, its frequency will increase.

Homework Equations


N/A

The Attempt at a Solution


It sounds perfect already. I don't see anything incomplete about it. When the index of refraction goes up, so does its frequency.


---------------------------------------------------------------------------------

Homework Statement


Visible light is usually seen in straight lines, while radio waves seem to be able to bend around houses and other similar sized objects. If they are both electromagnetic waves, why the apparent difference?

Homework Equations


n/a

The Attempt at a Solution


Does it have anything to do with light acting as both a particle and a wave?

Thanks in advance
 
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  • #2
Lennox786 said:

Homework Statement


I have to re-write the following statement because it is either incomplete or false. When an electromagnetic waves passes from one material into another with a higher index of refraction, its frequency will increase.

Homework Equations


N/A

The Attempt at a Solution


It sounds perfect already. I don't see anything incomplete about it. When the index of refraction goes up, so does its frequency.
What makes you think this? Something changes when waves change media, but what? Look it up.

Homework Statement


Visible light is usually seen in straight lines, while radio waves seem to be able to bend around houses and other similar sized objects. If they are both electromagnetic waves, why the apparent difference?

Homework Equations


n/a

The Attempt at a Solution


Does it have anything to do with light acting as both a particle and a wave?
No. Compare the length of the waves. What is this "bending around obstacles" called? (Look it up!)
 
  • #3
I did look up the first one, in my notes and on google. I am getting the same thing.

O i get it. Since radio waves have a larger wavelength, the diffraction (bending of a wave) will also increase. Visible light has a smaller wavelenghth, so its diffraction isn't as great and cannot bend the walls.
 
  • #4
Lennox786 said:
I did look up the first one, in my notes and on google. I am getting the same thing.
Are you saying you found physics sites that said that frequency of a wave increases when it passes into a medium of higher index of refraction? I hope not! (If so, give a reference and I'll check it out.)

O i get it. Since radio waves have a larger wavelength, the diffraction (bending of a wave) will also increase. Visible light has a smaller wavelenghth, so its diffraction isn't as great and cannot bend the walls.
Exactly.
 
  • #5
K i was thinking of wrong thing for first one.

If index of refraction increases, then diffraction increases, which really means that wavelenght increases. Since wavelength increases, then frequency goes down?
 
  • #6
Lennox786 said:
If index of refraction increases, then diffraction increases, which really means that wavelenght increases.
Nope.
Since wavelength increases, then frequency goes down?
How do you figure this?

Read this: http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html" [Broken]
 
Last edited by a moderator:
  • #7
ok so its unchanged.

Thanks for help
 
  • #8
Frequency of EM waves

Frequency of electromagnetic waves does not change when traveling through mediums of different index of refraction.
In fact, when a wave of frequency "f" in a medium of index "n1" passes to a medium of index "n2", the frequency of the wave does not change, but it is its wavelength that changes.

f = v1/λ1 = v2/λ2
where "vi" is the speed of light in medium i and "λi" is the wavelength of the electromagnetic wave.
and
vi = c/ni where "c" is the speed of light in free space and it equals 300,000,000m/s.

So we see that the speed of light in the medium and the wavelength change in a manner that the frequency remain constant.
 

1. What are electromagnetic waves?

Electromagnetic waves are a type of energy that is created by the movement of electrically charged particles. They are able to travel through a vacuum and do not require a medium, such as air or water, to propagate.

2. How are electromagnetic waves classified?

Electromagnetic waves are classified based on their wavelength and frequency. The electromagnetic spectrum includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

3. What is the speed of electromagnetic waves?

The speed of electromagnetic waves is approximately 3 x 10^8 meters per second, which is equivalent to the speed of light. This speed is a fundamental constant in physics and is denoted by the letter "c".

4. What are some practical applications of electromagnetic waves?

Electromagnetic waves have numerous practical applications in our daily lives. Some examples include radio and television broadcasting, cell phones, WiFi, microwave ovens, and medical imaging technologies such as X-rays and MRIs.

5. How do electromagnetic waves interact with matter?

Electromagnetic waves can interact with matter in different ways, depending on the properties of the material and the frequency of the wave. Some materials, such as metals, can reflect or absorb electromagnetic waves, while others can refract or diffract them. This interaction is the basis for technologies such as solar panels and optical fibers.

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