Why charges moving with contant velocity doesn't produce electromagnetic radiation or field? Explain with the reference of relativity theory? Since a charged particle produces an electric field all the time whether moving or not, but when it starts moving with constant velocity, it also starts producing a magnetic field along with an electric field...
So why doesn't it produces electromagnetic field or waves or radiation?
Since electric field combined with magnetic field and oscillating is an electromagnetic field.
And what does an accelerating charge does different as compared to a constant moving charge, so that it produces an EM field?
And one thing more... Suppose a charged particle is accelerating concerning an inertial frame, So as per that inertial frame it will produce an electromagnetic field. But at the same time, the same charge is not accelerating concerning a non-inertial frame (accelerating frame). So for a person which is in a non-inertial frame will that charged particle produce an electromagnetic wave?
I have some doubts please explain to me all this thing concerning relativity theory.
 A: I couldn't begin to reproduce the arguments from memory, not least because I don't understand tensor calculus, but the gist is:
A charge radiates if and only it is accelerating with respect to an inertial frame.
An accelerating observer will not observe radiation from an inertial charge.
An accelerating frame is equivalent to a stationary frame in a gravitational field; free-fall is an inertial frame.
Maxwell's Equations are only valid in an inertial frame (although a weak gravitational field such as Earth's allows for a close approximation; in particular, they work fine as long as the electric forces are much greater than the gravitational forces, so... most of the time).
A charge at rest w/r/t an accelerating frame or gravitational field does not appear to radiate even though it is accelerating and therefore must be radiating. (E.G. you can't measure radiation from stationary charges in a lab on Earth). This paradox went unsolved for many decades. Eventually it was resolved by analysis which proves that the radiation emitted is behind the event horizon of the non-inertial observer.
For a rigorous treatment of part of this problem see: arxiv.org/abs/physics/0506049
