Do magnetic forces obey Newton’s third law. Verify for two current elements located at the origin and located at (0, R, 0). Both carry current I.

Question

Philoid · Accepted Answer

No, it does not obey.

Magnetic field due to dl₁ at (0, R,0) is

So, the force on dl₁ from this magnetic field is;

Now, force on dl₁ due to dl₂ is 0.

This violates the 3^rd law.