Final answer:
Faraday's Law of Induction is used to determine the induced current in a coil due to a time-varying magnetic field from a nearby current-carrying wire.
Step-by-step explanation:
The physical principle relevant to determine the induced current in a coil due to a changing magnetic field produced by a nearby current-carrying wire is Faraday's Law of Induction. This law states that the magnitude of the induced electromotive force (emf) in a loop is equal to the negative rate of change of the magnetic flux through the loop. Considering a varying current I(t) = I0 * sin(ωt) in a long wire, it generates a time-varying magnetic field around it, which in turn induces an emf in the rectangular loop placed at a distance d from the wire. The induced current in the loop with resistance R is then given by the induced emf divided by R, according to Ohm's Law.