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Hi all. I am alluding to the Moving Charge in a Magnetic field problem by quoting an MIT lecture below.

In the quote, the author says, in the charge frame, the charge is at rest therefore there can be no magnetic force (Lorentz force). But this is incorrect since velocity is relative here. If the charge frame appears still, it's because the magnetic field lines (B) are moving at v in the Lorentz force equation. (F = qvB).

Current in a wire, for eg, is not zero if you pick a moving charge's frame, since the protons appear to move in the opposite direction. Therefore, current or magnetic field is never zero in a live wire, no matter which frame one picks: electrons or protons. This seems pretty pedestrian. What is going on here?

PS. Lorentz force: F = qvB, where v is the relative velocity between the charge q and a field line (B).

**Scott Huges**

*– Lecture*

*http://web.mit.edu/sahughes/www/8.022/lec10.pdf*

*Suppose we now examine this situation from the point of view of the charge (the “charge frame”). From the charge’s point of view, it is sitting perfectly still. If it is sitting still, there can be no magnetic force!*

In the quote, the author says, in the charge frame, the charge is at rest therefore there can be no magnetic force (Lorentz force). But this is incorrect since velocity is relative here. If the charge frame appears still, it's because the magnetic field lines (B) are moving at v in the Lorentz force equation. (F = qvB).

Current in a wire, for eg, is not zero if you pick a moving charge's frame, since the protons appear to move in the opposite direction. Therefore, current or magnetic field is never zero in a live wire, no matter which frame one picks: electrons or protons. This seems pretty pedestrian. What is going on here?

PS. Lorentz force: F = qvB, where v is the relative velocity between the charge q and a field line (B).

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