In one aspect, an apparatus for use in a wellbore is disclosed that in one non-limiting embodiment includes a string for placement in the wellbore and a switch on an outside of the string, wherein the switch includes a plurality of magnetic elements that provide a continuous electrical when the plurality of magnetic elements are aligned by an externally applied magnetic field. In one embodiment, the switch includes a channel that houses the plurality of magnetic elements that remain unaligned until the magnetic elements are aligned by the externally applied magnetic field.