Several optics/electromagnetics questions.

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In summary: These instruments measure the magnetic properties of a material, which can then be used to calculate the relative permeability. In summary, Alpha refers to the extinction coefficient and is related to the Beer-Lambert law, while the skin depth is related to the conductivity of a material. To calculate c through a Beer-Lambert experiment, you would need to know the absorbance and pathlength. The relative permeability can be measured using specialized instruments.
  • #1
ohadohad2
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Hello everybody,Im new here and I wondered if some of you can help.


1.Im kind of confused regarding Alpha (some links attachedm,Wiki links for simplicity) ,Im confused I am not sure if they all talk about the same thing or not.

Im currently doing a a project and we measure the absorption,trancmisence,conductivity and epsilno_R of materials and I want to cross check the Alpha with several theories.But now I am not sure that its the same Alpha.

http://en.wikipedia.org/wiki/Beer-Lambert_law
http://en.wikipedia.org/wiki/Extinction_coefficient#Extinction_coefficient
http://en.wikipedia.org/wiki/Skin_depth


2.Anyone knows how to get c through a Beer - Lambert experiment? I have A and L , but Alpha and c are both variables.

3.How can I measure Meu_R (permability)?


Thanks in advance for your time reading and awnsering this.
 
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  • #2
1. Alpha refers to the extinction coefficient and is related to the Beer-Lambert law, which states that the absorbance of a material is equal to the product of the extinction coefficient and the pathlength of the sample. The skin depth is related to the conductivity of a material and is not directly related to alpha. 2. To calculate c through a Beer-Lambert experiment, you would need to know the absorbance (A) and the pathlength (L). You can then use the equation A=ε*c*L to solve for c. 3. You can measure the relative permeability of a material by using an instrument such as a Permeameter or a Gaussmeter.
 
  • #3


Hello there,

I can definitely understand your confusion about Alpha, as it can refer to different things depending on the context. In this case, it seems like you are talking about the absorption coefficient, which is represented by the symbol α. This is a measure of how much light or electromagnetic radiation is absorbed by a material as it passes through it.

The Beer-Lambert law is one way to calculate the absorption coefficient, by using the relationship between the intensity of light passing through a material and its thickness. The extinction coefficient, on the other hand, is a measure of how much light is absorbed per unit of concentration of a substance. So while they are related, they are not exactly the same thing.

The skin depth is another concept related to absorption, but it specifically refers to how far into a material electromagnetic radiation can penetrate before its intensity is reduced by a factor of 1/e (about 37%). This is dependent on the frequency of the radiation and the material's properties.

In terms of getting c (I assume you mean the speed of light) through a Beer-Lambert experiment, you would need to know the values of A, L, and α. You can then use the equation c = αL/A to calculate the speed of light.

To measure the permittivity (ε_R) of a material, you can use various methods such as capacitance measurements or by measuring the reflection and transmission of electromagnetic waves through the material. It is important to note that permittivity is a complex quantity and is dependent on the frequency of the electromagnetic radiation.

I hope this helps clarify some of your questions. Good luck with your project!
 

1. What is the difference between optics and electromagnetics?

Optics is the branch of physics that deals with the behavior and properties of light, while electromagnetics is the study of the interactions between electric and magnetic fields. While optics focuses specifically on the properties of light, electromagnetics encompasses a much broader range of phenomena, including electricity, magnetism, and electromagnetic radiation.

2. How do lenses work?

Lenses work by refracting light, or bending it as it passes through the material of the lens. This bending of light allows the lens to focus an image by changing the direction of the light rays. Convex lenses, which are thicker in the middle and thinner at the edges, focus light to a point, while concave lenses, which are thinner in the middle and thicker at the edges, spread out light rays.

3. What is the electromagnetic spectrum?

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation, from low-frequency radio waves to high-frequency gamma rays. This spectrum includes various types of electromagnetic radiation, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

4. How do light waves and sound waves differ?

Light waves and sound waves are both forms of energy that travel through space, but they differ in several ways. Light waves are electromagnetic in nature, while sound waves are mechanical. Light waves can travel through a vacuum, while sound waves require a medium, such as air, to travel through. Light waves also travel much faster than sound waves.

5. What is the speed of light?

The speed of light in a vacuum is approximately 299,792,458 meters per second, or about 670 million miles per hour. This speed is considered the fastest possible speed in the universe, and it is a fundamental constant in physics. It can be calculated using the formula c = λν, where c is the speed of light, λ is the wavelength, and ν is the frequency of the light wave.

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