Question

Medal! Pls Help!

Using the right-hand rule for magnetic fields, when looking in the direction of the flow of current, which will be the direction of the magnetic field?

A. counterclockwise

B. clockwise

C. same direction as the flow of current

D. There is no rule for the direction of the magnetic field.

Answer 1

Just use the right-hand rule - point your right thumb away from you, and your fingers will be naturally curling and pointing in the direction of the magnetic field.

This is a 'parity' question, which means the real issue is getting the either/or answer right. Those kinds of questions (chemistry is almost nothing but) are always connected to each other via the principle causing the distinction, so find the ONE way you can always rely on to get it right, and then all the corollary questions will come along for the ride.

Further, it's a convention question, because the entire community has agreed to consider 'positive' the direction your fingers will be pointing when you point your thumb in the 'positive' direction for the current (which is the direction the electrons are moving.) You can do all the chemistry and physics using the wrong convention, and get the answers right, but you won't be able to talk to everyone else about it very easily.

(WARNING: the most important part of using this rule is to put your pencil in your left hand, because the most common mistake is using your left hand because your right hand was busy.)