Are Moving Electric Fields Equivalent to Magnetic Fields?

  • Thread starter Thread starter stmartin
  • Start date Start date
AI Thread Summary
Electric and magnetic fields are interrelated, as established in Einstein's 1905 paper "On The Electrodynamics Of Moving Bodies." In static conditions, such as in a magnetostatic scenario with a current-carrying loop, a magnetic field exists without an electric field in a stationary frame. Conversely, in an electrostatic condition with static charges, an electric field is present without a magnetic field in the rest frame. When observed from a moving reference frame, both electric and magnetic fields emerge due to relativistic effects. Ultimately, neither field is more fundamental than the other, highlighting their mutual coexistence in different reference frames.
stmartin
Messages
73
Reaction score
0
Moving electric field = magnetic field?
http://img65.imageshack.us/img65/1958/untitledet8.jpg
 
Last edited by a moderator:
Physics news on Phys.org
how come you ask?
 
https://www.physicsforums.com/showthread.php?t=175438&highlight=cabraham

This issue was thoroughly addressed in the above thread. Read through the entire thread and then we can discuss any questions you have. The crux of my contribution was Einstein's 1905 paper "On The Electrodynamics Of Moving Bodies".

The long and short of it, according to Albert Einstein himself, was that the electric and magnetic fields mutually coexist, and neither is more "fundamental" than the other. The point that some fail to acknowledge is that there are 2 "static" conditions, namely electrostatic, and magnetostatic.

A magnetostatic condition exists with a current carrying loop of steady (dc) value. A magnetic field surounds the wire, but there is zero electric field. This is with respect to the stationary reference frame. To an observer in a reference frame at motion wrt the rest frame (steady velocity, no acceleration), there will be an electric field as well as magnetic.

An electrostatic condition exists when static charges are separated, such as a capacitor charged to a steady (dc) voltage. In the rest frame, an electric field exists, with zero magnetic field. In a moving reference frame, again constant velocity w/ no accelaration, both electric and magnetic fields exist.

According to Einstein, neither the electric nor the magnetic field is the "seat". The term "seat" denoted the "root" or "basis" quantity. In conclusion, electric and magnetic fields are relativistically related.
 
Consider an extremely long and perfectly calibrated scale. A car with a mass of 1000 kg is placed on it, and the scale registers this weight accurately. Now, suppose the car begins to move, reaching very high speeds. Neglecting air resistance and rolling friction, if the car attains, for example, a velocity of 500 km/h, will the scale still indicate a weight corresponding to 1000 kg, or will the measured value decrease as a result of the motion? In a second scenario, imagine a person with a...
Thread 'Gauss' law seems to imply instantaneous electric field propagation'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Dear all, in an encounter of an infamous claim by Gerlich and Tscheuschner that the Greenhouse effect is inconsistent with the 2nd law of thermodynamics I came to a simple thought experiment which I wanted to share with you to check my understanding and brush up my knowledge. The thought experiment I tried to calculate through is as follows. I have a sphere (1) with radius ##r##, acting like a black body at a temperature of exactly ##T_1 = 500 K##. With Stefan-Boltzmann you can calculate...

Similar threads

Back
Top