[netrat]

stationary charge produces electric field
Constantly moving charge produces electric+ magnetic field
accelerated charge produces electric+magnetic+radiation(photons)

CASE 1:-
Two charged masses A and B are put side by side and an observer too. All being stationary.
Observer will only detect electric field from two masses.

Case 2:-
One Mass A starts moving at constant velocity away from observer while other mass B is stationary on the side of observer.
Observer will detect electric and magnetic fields from moving mass A, and only electric field from stationary mass B.
If observer starts moving at same velocity as that of A, magnetic field from A disappears, only electric field is detected from A. While B now produces electric+magnetic fields.

Case 3:-
Mass A accelerates away from stationary observer and mass B.
Observer detects electric+magnetic fields and also sees photons emitted from A, while only electric field is detected from B.
If observer accelerates at same acceleration as A, magnetic field and photons disappear and only electric field is detected from A, while mass B now produces electric+magnetic fields and Photons.

EXTREME CASE:-
Mass A accelerates,
two observers observer mass A. If both are stationary both receive electric+magnetic fields and also See the photons emitted from A.
if one observer accelerates with same acceleration as A, he doesn't see the photons anymore, only gets the electric field while the other stationary observer still sees the photons.

<<<<Explanation please>>>>

[ajb]

You don't need to worry about photons, just thinking about the electric and magnetic fields is enough.

The point here is that it is that it is unphysical to think about the electric and magnetic fields as being separate things. In more technical language it is not a Lorentz covariant notion. By a Lorentz transformation you can "mix" the electric and magnetic fields. What one needs to think about the electromagnetic field.

[Bob_for_short]

zacinfinite, on 6 September 2010 - 03:35 AM, said:

Case 3:-
Mass A accelerates away from stationary observer and mass B.
Observer detects electric+magnetic fields and also sees photons emitted from A, while only electric field is detected from B.

If observer accelerates at same acceleration as A, magnetic field and photons disappear and only electric field is detected from A, while mass B now produces electric+magnetic fields and Photons.

Photons from A do not disappear in an accelerated reference frame. The radiated EMF energy density is positive and cannot be canceled with a variable change. The emitted photons can be "registered" by a photomultiplier or reflected by a mirror, so their presence is easily visible in an accelerated RF.

This post has been edited by Bob_for_short: 6 September 2010 - 05:25 PM