Question

The magnetic vector potential at any point is A=5(x*2+y*2+z*2)i. Evaluate the magnetic field at that point.

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Answer 1

Answer:

Take a thick straight conductor XY and pass it through the centre of a thick cardboard. Pass current through the conductor such that it flows from X to Y. Sprinkle some iron filings on the cardboard and gently tap. You will see that the iron filings arrange themselves in concentric circles around the wire.