# How to define an inertial frame w.r.t. an electromagnetic field? [closed]

Can you give an example of an inertial frame in presence of an electromagnetic field for all kinds of charged particles?

## closed as unclear what you're asking by Ben Crowell, Jon Custer, ZeroTheHero, John Rennie, ChairFeb 11 at 7:28

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• Hi user341778. I removed your second subquestion. Phys.SE prefers 1 subquestion per post. – Qmechanic Feb 10 at 14:04
• It is not at all clear what this would mean. Inertial frames are not typically defined "with respect to" anything, let alone an electromagnetic field. – Luke Pritchett Feb 10 at 14:28

• I think the correct statement is that if $\vec{E} \cdot \vec{B} = 0$ and $|E| > |B|$, then there is a frame in which $\vec{B} = 0$; and if $\vec{E} \cdot \vec{B} = 0$ and $|B| > |E|$, then there is a frame in which $\vec{E} = 0$. Your post conflates the two cases. – Michael Seifert Feb 10 at 15:05
• My point was that your point only says "$|E| > |B|$", which might lead someone to believe that this doesn't hold when $|B| > |E|$. – Michael Seifert Feb 11 at 3:27