A2L Item 230
- Description: Identify the correct expression for the magnetic field at the center of a current loop.
- Goal: Applying the Biot-Savart law
- Source: 283-645 Magnetic field from wire loop
- Keywords: Current, Electromagnetism, Magnetic Field
The question for students:
The diagram shows a circular wire loop of radius R carrying current I. What is the magnitude of the magnetic field, B, at the center of the loop?
- 0
- μ0I/4πR
- μ0I/2πR
- μ0I/4R
- μ0I/2R
- None of the above.
Commentary for teachers:
Answer
(5) This question serves to identify students who do not know how to apply the Biot-Savart law and/or those who are recalling the field due to an infinite wire. This provides a good opportunity to discuss why Ampere’s law is inappropriate for this case.