12.3 Interacting Magnets
When two bar magnets are placed near one another, the fields interact. The absence of filings between the poles in this photo is an indication of opposing magnetic fields. In this example, the two magnets are repelling one another. Perhaps you can see the field lines between the two magnets as almost perpendicular to the lengths of the magnets.
Watch ThisExplore the magnetic field surrounding two bar magnets and how to represent magnetic fields in three dimensions using the interactive tutorial Two Magnets . What you draw on paper for a magnetic field depends on your point of view. Summarize the three different magnetic field representations. Recall that in previous lessons the gravitational and electric fields were described by three-dimensional regions of influence. The magnetic field shares this similarity. |
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Magnetic fields tend to be stronger near the poles of magnets (or near Earth's poles). Earth's magnetic field strength in this region is about 6 × 10 −5 T. A typical 10-g bar magnet has a magnetic field near its poles of about 2 × 10 −2 T.
On occasion you may also see the strength of a magnetic field described using the term "flux."
Self-CheckAnswer the following self-check (SC) questions then click the "Check your work" bar to assess your responses. |
SC 1.
Each diagram shows two equal-strength bar magnets with test objects around them. Indicate the polarity of the bar magnets in each diagram.
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b.
c
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SC 2.
Each diagram shows two equal-strength bar magnets. Draw the magnetic field lines that would surround the pair of magnets.
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b.
c.
d.
Self-Check Answer
SC 1.
Contact your teacher if your answers vary significantly from the answers provided here.
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b.
c.
d.
SC 2.
Your field lines should look similar to those shown below.
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b.
c.
d.
SC 1.
Contact your teacher if your answers vary significantly from the answers provided here.
a.
b.
c.
d.
SC 2.
Your field lines should look similar to those shown below.
a.
b.
c.
d.