Electric and magnetic field relationship

AI Thread Summary
The electric field E(x, y, z, t) and magnetic field B(x, y, z, t) presented are invalid because they do not satisfy the requirements of Maxwell's equations. Specifically, both fields must propagate in the same direction, necessitating that they share the same phase term, either (kz-wt) or (kz+wt). The differing phase terms indicate a violation of the relationship between electric and magnetic fields in electromagnetic waves. Additionally, the cross product of these fields results in a standing wave, which is inconsistent with the behavior of propagating electromagnetic waves. Therefore, the fields cannot coexist as valid solutions in classical electromagnetism.
erisedk
Messages
372
Reaction score
7

Homework Statement


Why is the following set of electric and magnetic fields invalid?
##E(x, y, z, t)= E_0 \sin{(kz-wt)} \hat{i}##

##B(x, y, z, t) = B_0 \sin{(kz+wt)} \hat{j}##

Homework Equations

The Attempt at a Solution


So, I understand that either both should have (kz-wt) or both should have (kz+wt). Either than the fact that the cross product of electric and magnetic fields is a scalar times a vectors that does not depend on time, whereas here the cross product gives me something like a standing wave in the z direction, I'm not sure why both should have (kz-wt) or both should have (kz+wt). Please help.
 
Physics news on Phys.org
Have you studied Maxwell's equations?
 
Yes
 
If you can show that anyone of Maxwell's equations is violated at some point of space at some instant of time, then the fields are invalid.
 
  • Like
Likes cnh1995
Thank you! Got it.
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanged mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top