# magnetic force/electric field/magnetic field

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Can anyone please help me on Question #7 on Physics Passage 12 on TPR In-Class Compendium??? I am sooo confused how an electric field produced by magnetic force will create another magnetic field... So ions (Na+ and Cl-) are moving into the plane of the page, magnetic field from left to right wall of the artery, so magnetic force downward, right? Then, chloride ions (- charged ions) move upward in an artery because of the magnetic force, and the question is to describe the magnetic field created by the movement of the chloride ions in the artery... The answer is counterclockwise around the artery.

Sooo confused...

Thanks!

#### crazybob

using F = qv X B, you can use the right hand rule.

for sodium, it travels in the plane of the page, so you stick your four fingers out. the magnetic field is from left to right, so you need to curl your hands to the right. the only way that is done is by pointing your thumb down. so the magnetic force on the sodium is downward.

for chlorine, it travels in the plane of the page also. so if you stick your four fingers out, you need to curl your hands again to the right. but chlorine is negative, so you use your left hand. and your thumb points upward.

and so the movement of the chlorine ions is first into the page, and then in a circle upward because of the magnetic force. if you go from out, up, in, down, out, up, in, down, etc, it's in the counterclockwise direction when viewed from the right side.