| Unit 1: Active Physics | ||
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6. A hollow, transparent plastic tube is placed on a horizontal surface as shown in the diagram. A wire carrying a current is wound once around the tube to form a circular loop in the wire. In what direction would a compass placed inside the tube point? (Plastic does not affect a compass; only the current in the wire loop will affect the compass.)
Stretching Exercises Use a compass to search for magnetic effects and magnetic “stuff.” As you know, a compass needle usually aligns in a north-south direction (or nearly so, depending on where you live). If a compass needle does not align north-south, a magnetic effect in addition to that of the Earth is the cause, and the needle is responding to both the Earth’s magnetism and some other source of magnetism. Use a compass as a probe for magnetic effects. Try to find magnetic effects in a variety of places and near a variety of things where you suspect magnetism may be present. Try inside a car, bus, or subway. The structural steel in some buildings is magnetized and may cause a compass to give a “wrong” reading. Try near the speaker of a radio, stereo, or TV. Try near electric motors, both operating and not operating. Do not bring a known strong magnet close to a compass, because the magnet may change the magnetic alignment of the compass needle, destroying the effectiveness of the compass. Make a list of the magnetic objects and effects that you find in your search. |
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