A metal detector with two coils (an exciter and a detector) is an example an active detection system. Suppose a metallic coin (which is non-magnetic on its own, but can have a magnetic field induced by an exciter coil) is lost under the sand at the beach. Part A The exciter coil would use electric current. The detector coil will detect a signal from the lost coin under the sand because 6E · al = at an AC, $B· al = µo(! + €o °E) an AC, $E · Əl = =0e a DC, at $B· al = Ho(! + €o a DC, at

A metal detector with two coils (an exciter and a detector) is an example an active detection system. Suppose a metallic coin (which is non-magnetic on its own, but can have a magnetic field induced by an exciter coil) is lost under the sand at the beach. Part A The exciter coil would use electric current. The detector coil will detect a signal from the lost coin under the sand because 6E · al = at an AC, $B· al = µo(! + €o °E) an AC, $E · Əl = =0e a DC, at $B· al = Ho(! + €o a DC, at