Finding Maxwell's Equation parameters problem

[baby_1]

Homework Statement

Homework Equations

http://esclab.tw/wiki/images/math/0/a/2/0a24f9d68ba8fd1a1a8e6c6b36a00be3.png

The Attempt at a Solution

[/B]

Hello
As you see the answers of 19 and 20 problems we should try to find K or B(wave number) in wave equation.both of equations are in air space but we can't use K=(2*pi*f)/V ( F=frequency & 2*pi*f=omega , V= light velocity 3*10^8) for both of them.
could you tell me why we can't use the K=(2*pi*f)/V for both of them in air space?does it have any condition & reason that we should check them before solve the problems?

Any help appreciated

 

[Simon Bridge]

could you tell me why we can't use the K=(2*pi*f)/V for both of them

Both of what? Both problems?
Where does that relation come from?

 

[baby_1]

Thank you dear simon for you replay
My meaning is why in problem (6-19) should we use k=w/c but in problem(6-20) we should not?

Where does that relation come from?

your meaning is K=w/c?

 

[Simon Bridge]

I mean - what physical property of the wave does k represent.

The second case is in a medium - what is different about EM waves traveling in a medium compared with a vacuum?
hint: if you took k=w/c for the second case, you could not use c=3x10^8m/s.

 

[HalfLostAndSearching]

Dear student,

Thank you for your question. In order to find the parameters in Maxwell's equations, it is important to understand the physical conditions and assumptions that are involved. In the provided equations, we can see that the first equation is in terms of the electric field (E) and the second equation is in terms of the magnetic field (B). These fields are related to each other through the speed of light (c) and the wave number (k).

The equation K=(2*pi*f)/V is commonly used to calculate the wave number in free space, where the speed of light is known to be constant. However, in air space, the speed of light can vary depending on factors such as temperature, humidity, and pressure. Therefore, this equation cannot be used directly for both of the given problems as we do not have enough information about the specific conditions in the air space.

In order to find the wave number for these problems, we need to take into account the specific conditions of the air space and use the appropriate equations. For example, we could use Snell's law to calculate the wave number if the problem involves a change in the medium. Additionally, we could also use the refractive index of air to calculate the wave number.

In conclusion, it is important to carefully consider the physical conditions and assumptions involved in a problem before attempting to solve it. I hope this helps to clarify the issue and guide you in finding the correct parameters for Maxwell's equations.

Best regards,