Delwell SC CV
53. Mutual induction can be used as the basis for a metal
detector. A typical set-up 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 hand gun 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.​