What Are the Units of Electromagnetic Wave B?

AI Thread Summary
The discussion focuses on deriving the units for the magnetic field B in electromagnetic waves using the equation B = k / w (Z x E). Key points include the definitions of variables such as k (wave number), w (angular frequency), and E (electric field), with discussions on their respective units. The participants clarify that B can be expressed in terms of velocity, leading to the conclusion that B has units of [A] (amperes). There is a caution about the distinction between voltage (V) and velocity (v) due to potential confusion in notation. Overall, the derivation emphasizes the importance of unit consistency in electromagnetic wave equations.
dowjonez
Messages
21
Reaction score
0
B = k / w ( Z x E)

Check this equation by deriving the units for B


w = omega
Z = z hat
 
Physics news on Phys.org
What have you done so far?
 
k = 2pi / lamdba
w = 2 pi V / lamba

So B = 1/V ( Z X E)

B = 1/ [ m / s ] ( Z X E )

[E] = [q] / [E0] [ R^2]

[E] = [C] / [C^2/ Nm^2] [ m^2] = [N / C]

B = [s / m] * ( Z x [N / C])
 
but = N / A * m
 
[C / s] = [A], so 1/[A] = [s / C]

[N] / [Am] = [N / m]*[1/A], right? so [N]/[Am] = [s/C]*[N/m], or [s/m]*[N/C]

I may have missed something, but I don't see a problem.

Also, be careful. V = voltage, v = velocity. It was hard to read your posts with some of those things in caps. This could have been easier if you noticed immediately that k/w = 1/v, which has units [s/m], and that E always has units [N/C]. Maybe you were expected to work it all out, but that's silly.
 
Last edited:

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Direction of travel of a plane wave given direction of electric field
Replies
8
Views
1K
Progressive wave, wavelength moving in the opposite direction
Replies
4
Views
1K
Textbook 'The Physics of Waves': Reason to force us to consider complex solution for harmonic motion?
Replies
3
Views
919
How Do Electromagnets Repel Each Other in a Zero-Resistance Environment?
Replies
6
Views
1K
EM Wave Reflection and Transmission Between 3 Materials
Replies
12
Views
2K
Trying to understand electromagnetism
Replies
38
Views
3K
Problem about electromagnetic waves -- Writing equations for B(t) and E(t)
Replies
2
Views
1K
Unit Vectors for Polarization and Wave Vector Directions
Replies
3
Views
2K
Writing a vector parallel and normal to a unit vector ##\hat n##
Replies
26
Views
1K
An Electromagnetic wave goes from air into a medium....
Replies
3
Views
3K

Hot Threads

Recent Insights

Back
Top