→
WHAT’S HAP
PENING?
Exchanging poles
YOU WILL NEED
→ setup from Experiment 28
HERE'S HOW
1. Repeat the last experiment. Pay
attention to which end of the compass
needle points to the coil.
2. Then place the compass at the other
end of the coil, and briefly switch on
the current.
Which end of the compass needle points
to the coil now?
3. Repeat this experiment, but first reverse
the battery terminals so the current
flows the opposite direction through
the wire.
What are the positions of the needle
this time?
The current flo
w really does
transform the c
oil into a mag
net,
and this elect
romagnet has a
north and a so
uth pole just l
ike a
bar magnet — a
s the compass
needle clearly
shows. And w
hen
the current flo
ws the opposi
te
direction thro
ugh the coil, t
he
magnetic pole
s of the
electromagne
t switch as we
ll.
2
3
1
Electromagnetism |
41
EXPERIMENT 29
Summary of Contents for 665050
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