Goal: Hone the right-hand-rule for vector cross products
Source: 283-640 B direction from wire loop
The diagram shows a circular wire loop of radius R carrying current I.
What is the direction of the magnetic field, B, at the center of the
loop?
- Left
- Right
- Up
- Down
- None of the above
Commentary:
Answer
(3) This is the best response given the choices. The question poses
little difficulty for students who have learned about the magnetic field
of current loops as a magnetic dipole. For these students this question
just confirms their knowledge. For students who are trying to apply the
Biot-Savart law to the loop as a set of current elements the question is
more challenging.