A2L Item 180
- Description: Identify locations where the total magnetic field due to two bar magnets is zero?
- Goal: Reason about magnetic fields
- Source: 283 field of bar magnets
- Keywords: Electromagnetism, Magnetic Field
The question for students:
Two
identical bar magnets are placed rigidly and parallel to each other as
shown. At what locations, if any, is the net magnetic field close to
zero?
- A only
- B only
- C only
- D only
- A and B
- A, B, and C
- C and D
- None of the above.
Commentary for teachers:
Answer
(3) C is the point of weakest field. The field is weak at A also. Find out student reasons is more important than the answer. Have students sketch the field lines. Ask them how is the strength of the field indicated on a field line diagram.