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53. Mutual induction can be used
as the basis for a metal detector. A typical setup uses two large coils that
are parallel to each other and have a common axis. Because of mutual
induction, the ac generator connected to the primary coil causes an emf of
0.46 V to be induced in the secondary coil. When
someone without metal objects walks through the coils, the mutual inductance
and, thus, the induced emf do not change much. But
when a person carrying a handgun walks through, the mutual inductance
increases. The change in emf can be used to trigger
an alarm. If the mutual inductance increases by a factor of three, find the
new value of the induced emf. |
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So for original case we have |
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So for the handgun case |
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