Verifying Answer to Wave Equation and Associated B Field

In summary, we have a question about deriving the wave equation for the electric field in empty space and checking if a given plane wave solution is valid. The solution involves using Maxwell II and separation of variables to find the electric field and using curlE = -dB/dt to find the associated magnetic field. However, there seems to be a disagreement on how to calculate the curl of E, with one person suggesting it is just the value of E integrated with respect to x and the other saying it should have two components along the x1 and x3 axes. Further clarification is needed.
  • #1
Hoofbeat
48
0
Hi, I have the following question on my problem sheet, and I just want to check that my answer to it is correct as I need to use the result in a later problem. If someone could confirm it is correct, or point out mistakes/erros that would be great.

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Q. Derive the wave equation for E in empty space (Form the curl of Maxwell II and use a vector identity.). Find the condition that the plane wave E = eyEycos(wt - kx) is a solution (k=2pi/lamda). Use Maxwell II to find the B field associated with this electric field.
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A. I've done the derivation fine to get:

Laplacian E = epsilon-0.mu-0. d^2E/dt^2 [these are partial derivatives]

this is the same as d^2E/dx^2 = (1/c^2).(d^2E/dt^2) which can be solved using separation of variables to get E = eyEycos(wt - kx).

To find the associated B field, we used Maxwell II, ie. curlE = -dB/dt.

CurlE = -keyEysin(wt - kx)

B = integral - [curl E] dt

B = k/w. eyEycos(wt - kx)

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Thanks
 
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  • #2
[tex] \vec{B}=-\int dt \nabla\times\vec{E} [/tex]

What is the curl of [itex] \vec{E} [/itex]...?And then evaluate the integral correctly.

Daniel.
 
  • #3
dextercioby said:
[tex] \vec{B}=-\int dt \nabla\times\vec{E} [/tex]

What is the curl of [itex] \vec{E} [/itex]...?And then evaluate the integral correctly.

Daniel.

Isn't the curl of E in this case, just the value of E calculated earlier, integrated wrt x?
 
  • #4
That curl is a vector and should have 2 components,namely on [itex] Ox_{1}[/itex] and [itex] Ox_{3} [/itex] axis of coordinates...

So it's incorrect what you have written.Please do the calculations again.

Daniel.
 

1. What is the wave equation and associated B field?

The wave equation is a mathematical equation that describes the behavior of waves. It is commonly used to model physical phenomena such as sound, light, and electromagnetic waves. The associated B field refers to the magnetic field that is generated by a moving electric charge.

2. How do you verify the answer to the wave equation and associated B field?

The answer to the wave equation and associated B field can be verified through experimental observations and mathematical calculations. This involves measuring the properties of the wave, such as its frequency and wavelength, and comparing them to the predicted values from the wave equation. Additionally, the B field can be measured using a magnetometer to confirm its presence and strength.

3. What factors affect the wave equation and associated B field?

The wave equation and associated B field are affected by several factors, including the properties of the medium through which the wave is traveling, the frequency and amplitude of the wave, and the presence of any external magnetic fields. Additionally, the wave equation and B field can be altered by the presence of electric charges or currents in the medium.

4. Are there any real-world applications of the wave equation and associated B field?

Yes, the wave equation and associated B field have numerous real-world applications. They are used in fields such as acoustics, optics, and electromagnetism to study and understand various phenomena. For example, the wave equation is used to model and predict the behavior of sound waves in musical instruments, and the associated B field is crucial in the design and functioning of devices such as MRI machines and electric motors.

5. Are there any limitations to the wave equation and associated B field?

While the wave equation and associated B field are powerful tools for understanding and predicting wave behavior, they do have some limitations. For example, the wave equation assumes a uniform and linear medium, which may not always be the case in real-world scenarios. Additionally, the associated B field may be affected by external factors, such as temperature and pressure, which can alter its behavior and make it difficult to predict accurately.

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